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id=\"rr_wrapper1695\" class=\"rr_wrapper\" postid=\"1695\"><\/div>\r\n\t<div id=\"rr_content1695\"> <h3>100. The Art And Science Of Navigation<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1398\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1370\/img_3586#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3586.jpg\" data-orig-size=\"2048,1536\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;2.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 3GS&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1403788770&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;3.85&quot;,&quot;iso&quot;:&quot;160&quot;,&quot;shutter_speed&quot;:&quot;0.058823529411765&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"IMG_3586\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3586-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3586-1024x768.jpg\" class=\"size-medium wp-image-1398 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3586-300x225.jpg\" alt=\"IMG_3586\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3586-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3586-1024x768.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3586.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>Marine navigation blends both science and art. A good navigator constantly thinks strategically, operationally, and\u00a0tactically. He plans each voyage carefully. As it proceeds,\u00a0he gathers navigational information from a variety of\u00a0sources, evaluates this information, and determines his\u00a0ship\u2019s position. He then compares that position with his\u00a0voyage plan, his operational commitments, and his predetermined\u00a0\u201cdead reckoning\u201d position. A good navigator\u00a0anticipates dangerous situations well before they arise, and\u00a0always stays \u201cahead of the vessel.\u201d He is ready for navigational\u00a0emergencies at any time. He is increasingly a\u00a0manager of a variety of resources&#8211;electronic, mechanical,\u00a0and human. Navigation methods and techniques vary with\u00a0the type of vessel, the conditions, and the navigator\u2019s\u00a0experience. The navigator uses the methods and techniques\u00a0best suited to the vessel, its equipment, and conditions at\u00a0hand. Some important elements of successful navigation\u00a0cannot be acquired from any book or instructor. The science\u00a0of navigation can be taught, but the art of navigation must\u00a0be developed from experience.<\/p>\n<h3>101. Types of Navigation<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1542\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/100_0697#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0697.jpg\" data-orig-size=\"4608,2592\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;3.9&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1403626988&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.1&quot;,&quot;iso&quot;:&quot;320&quot;,&quot;shutter_speed&quot;:&quot;0.025&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_0697\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0697-300x168.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0697-1024x576.jpg\" class=\"size-medium wp-image-1542 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0697-300x168.jpg\" alt=\"100_0697\" width=\"300\" height=\"168\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0697-300x168.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0697-1024x576.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>Methods of navigation have changed throughout\u00a0history. New methods often enhance the mariner\u2019s ability to\u00a0complete his voyage safely and expeditiously, and make his\u00a0job easier. One of the most important judgments the\u00a0navigator must make involves choosing the best methods to\u00a0use. Each method or type has advantages and\u00a0disadvantages, while none is effective in all situations.\u00a0Commonly recognized types of navigation are listed below.<\/p>\n<ul>\n<li>Dead reckoning (DR) determines position by\u00a0advancing a known position for courses and\u00a0distances. A position so determined is called a dead\u00a0reckoning (DR) position. It is generally accepted that<\/li>\n<li>only course and speed determine the DR position.\u00a0Correcting the DR position for leeway, current\u00a0effects, and steering error \u00a0result in an estimated\u00a0position (EP).<\/li>\n<li>Piloting involves navigating in restricted waters\u00a0with frequent or constant determination of position\u00a0relative to nearby geographic and hydrographic\u00a0features.<\/li>\n<li>Celestial navigation involves reducing celestial\u00a0measurements taken with a sextant to lines of\u00a0position using calculators or computer programs, or\u00a0by hand with almanacs and tables or using spherical\u00a0trigonometry.<\/li>\n<li>Radio navigation uses radio waves to determine\u00a0position through a variety of electronic devices.<\/li>\n<li>Radar navigation uses radar to determine the\u00a0distance from or bearing of objects whose position is\u00a0known. This process is separate from radar\u2019s use in\u00a0collision avoidance.<\/li>\n<li>Satellite navigation uses radio signals from\u00a0satellites for determining position.<\/li>\n<\/ul>\n<div id=\"attachment_255\" style=\"width: 306px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-255\" data-attachment-id=\"255\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/san-juan-islands-2011\/lopez-island-2#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Lopez-Island-2.jpg\" data-orig-size=\"3648,2736\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;4.6&quot;,&quot;credit&quot;:&quot;Picasa&quot;,&quot;camera&quot;:&quot;COOLPIX S220&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1311441339&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;6.3&quot;,&quot;iso&quot;:&quot;80&quot;,&quot;shutter_speed&quot;:&quot;0.0010260619741432&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Lopez Island 2\" data-image-description=\"&lt;p&gt;&lt;em&gt;&lt;\/p&gt;\n\" data-image-caption=\"&lt;p&gt;Rafting at Spencer Spit with &amp;#8220;Ahelani,&amp;#8221; my sister&amp;#8217;s Outbound 48.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Lopez-Island-2-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Lopez-Island-2-1024x768.jpg\" class=\"size-medium wp-image-255\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Lopez-Island-2-300x225.jpg\" alt=\"Rafting at Spencer Spit with &quot;Ahelani,&quot; my sister's Outbound 48.\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Lopez-Island-2-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Lopez-Island-2-1024x768.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><p id=\"caption-attachment-255\" class=\"wp-caption-text\">Rafting at Spencer Spit with &#8220;Ahelani,&#8221; my sister&#8217;s Outbound 48.<\/p><\/div>\n<p>Electronic systems and integrated bridge concepts are driving navigation system planning. Integrated systems take inputs from various ship sensors, electronically and automatically chart the position, and provide control signals required to maintain a vessel on a preset course. The navigator becomes a system manager, choosing system presets, interpreting system output, and monitoring vessel response. In practice, a navigator synthesizes different methodologies\u00a0into a single integrated system. He should never\u00a0feel comfortable utilizing only one method when others are\u00a0also available. Each method has advantages and\u00a0disadvantages. The navigator must choose methods\u00a0appropriate to each situation, and never rely completely on\u00a0only one system. With the advent of automated position fixing and\u00a0electronic charts, modern navigation is almost completely\u00a0an electronic process. The mariner is constantly tempted to\u00a0rely solely on electronic systems. But electronic navigation\u00a0systems are always subject to failure, and the professional\u00a0mariner must never forget that the safety of his ship and\u00a0crew may depend on skills that differ little from those\u00a0practiced generations ago. <img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1199\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/friendship-salem#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/06\/Friendship-Salem.jpg\" data-orig-size=\"3648,2736\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;4.6&quot;,&quot;credit&quot;:&quot;Picasa&quot;,&quot;camera&quot;:&quot;COOLPIX S220&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1276525015&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;6.3&quot;,&quot;iso&quot;:&quot;80&quot;,&quot;shutter_speed&quot;:&quot;0.0026525198938992&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Friendship Salem\" data-image-description=\"&lt;p&gt;Friendship docked at Salem&lt;\/p&gt;\n\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/06\/Friendship-Salem-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/06\/Friendship-Salem-1024x768.jpg\" class=\"size-medium wp-image-1199 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/06\/Friendship-Salem-300x225.jpg\" alt=\"Friendship Salem\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/06\/Friendship-Salem-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/06\/Friendship-Salem-1024x768.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>Proficiency in conventional\u00a0piloting and celestial navigation remains essential.<\/p>\n<h3>102. Phases of Navigation<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1559\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/100_1195#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1195.jpg\" data-orig-size=\"2592,4608\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;5.7&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1404354796&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;25.3&quot;,&quot;iso&quot;:&quot;160&quot;,&quot;shutter_speed&quot;:&quot;0.005&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_1195\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1195-168x300.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1195-576x1024.jpg\" class=\"size-medium wp-image-1559 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1195-168x300.jpg\" alt=\"100_1195\" width=\"168\" height=\"300\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1195-168x300.jpg 168w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1195-576x1024.jpg 576w\" sizes=\"auto, (max-width: 168px) 100vw, 168px\" \/>Four distinct phases define the navigation process. The\u00a0mariner should choose the system mix that meets the\u00a0accuracy requirements of each phase.<\/p>\n<ol>\n<li>Inland Waterway Phase: Piloting in narrow canals,\u00a0channels, rivers, and estuaries.<\/li>\n<li>Harbor\/Harbor Approach Phase: Navigating to a\u00a0harbor entrance through bays and sounds, and\u00a0negotiating harbor approach channels.<\/li>\n<li>Coastal Phase: Navigating within 50 miles of the\u00a0coast or inshore \u00a0of the 200 meter depth contour.<\/li>\n<li>Ocean Phase: Navigating outside the coastal area in\u00a0the open sea.<\/li>\n<\/ol>\n<p>The navigator\u2019s position accuracy requirements, his fix\u00a0interval, and his systems requirements differ in each phase.\u00a0The following table can be used as a general guide for\u00a0selecting the proper system(s). Inland Harbor\/ Approach Coastal Ocean DR X X X X Piloting X X X Celestial X X Radio X X X Radar X X X Satellite X* X X X<\/p>\n<h3>103. Important Conventions and Concepts<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1538\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/100_1574#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1574.jpg\" data-orig-size=\"4608,2592\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;4.6&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1405158618&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;8.7&quot;,&quot;iso&quot;:&quot;400&quot;,&quot;shutter_speed&quot;:&quot;0.02&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_1574\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1574-300x168.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1574-1024x576.jpg\" class=\"size-medium wp-image-1538 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1574-300x168.jpg\" alt=\"100_1574\" width=\"300\" height=\"168\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1574-300x168.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1574-1024x576.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>Throughout the history of navigation, numerous terms and conventions have been established which enjoy worldwide recognition. The professional navigator, to gain a full understanding of his field, should understand the origin of certain terms, techniques, and conventions. The following section discusses some of the important ones. Defining a prime meridian is a comparatively recent\u00a0development. Until the beginning of the 19th century, there was little uniformity among cartographers as to the meridian from which to measure longitude. But it mattered little because there existed no method for determining longitude accurately. Ptolemy, in the 2nd century AD, measured longitude eastward from a reference meridian 2 degrees west of the Canary Islands.<\/p>\n<div id=\"attachment_1736\" style=\"width: 306px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1736\" data-attachment-id=\"1736\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/img_3551#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3551.jpg\" data-orig-size=\"2048,1536\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;2.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 3GS&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1403785912&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;3.85&quot;,&quot;iso&quot;:&quot;640&quot;,&quot;shutter_speed&quot;:&quot;0.076923076923077&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Quadrant\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;Quadrant (15th Century) Instrument used for measuring the altitude of the stars in order to calculate the latitude. First made in wood, like this replica, they were later made of brass or bronze.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3551-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3551-1024x768.jpg\" class=\"size-medium wp-image-1736\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3551-300x225.jpg\" alt=\"Quadrant (15th Century) Instrument used for measuring the altitude of the stars in order to calculate the latitude. First made in wood, like this replica, they were later made of brass or bronze.\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3551-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3551-1024x768.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3551.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><p id=\"caption-attachment-1736\" class=\"wp-caption-text\">Quadrant (15th Century) Instrument used for measuring the altitude of the stars in order to calculate the latitude. First made in wood, like this replica, they were later made of brass or bronze.<\/p><\/div>\n<p>In 1493, Pope Alexander VI established a line in the Atlantic west of the Azores to divide the territories of Spain and Portugal. For many years, cartographers of these two countries used this dividing line as the prime meridian. In 1570 the Dutch cartographer Ortelius used the easternmost of the Cape Verde Islands. John Davis, in his 1594 The Seaman\u2019s Secrets, used the Isle of Fez in the Canaries because there the variation was zero. Most mariners paid little attention to these conventions and often reckoned their longitude from several different capes and ports during a voyage. The meridian of London was used as early as 1676, and\u00a0over the years its popularity grew as England\u2019s maritime\u00a0interests increased. The system of measuring longitude both\u00a0east and west through 180\u00b0 may have first appeared in the\u00a0middle of the 18th century. Toward the end of that century,\u00a0as the Greenwich Observatory increased in prominence,\u00a0English cartographers began using the meridian of that\u00a0observatory as a reference. The publication by the\u00a0Observatory of the first British Nautical Almanac in 1767\u00a0further entrenched Greenwich as the prime meridian. An\u00a0unsuccessful attempt was made in 1810 to establish\u00a0Washington, D.C. as the prime meridian for American\u00a0navigators and cartographers. In 1884, the meridian of\u00a0Greenwich was officially established as the prime meridian.\u00a0Today, all maritime nations have designated the Greenwich\u00a0meridian the prime meridian, except in a few cases where\u00a0local references are used for certain harbor charts.<\/p>\n<p style=\"text-align: left;\">Charts are graphic representations of areas of the\u00a0Earth, in digital or graphic form, for use in marine or air\u00a0navigation. Nautical charts, whether in digital or paper\u00a0form, depict features of particular interest to the marine\u00a0navigator. Charts have probably existed since at least 600\u00a0B.C. Stereographic and orthographic projections date from\u00a0the 2nd century B.C. <img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"766\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/765\/wrldmap#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/03\/wrldmap.gif\" data-orig-size=\"268,122\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"wrldmap\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/03\/wrldmap.gif\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/03\/wrldmap.gif\" class=\"size-full wp-image-766 aligncenter\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/03\/wrldmap.gif\" alt=\"wrldmap\" width=\"268\" height=\"122\" \/>In 1569 Gerardus Mercator published\u00a0a chart using the mathematical principle which now bears\u00a0his name. Some 30 years later, Edward Wright published\u00a0corrected mathematical tables for this projection, enabling\u00a0other cartographers to produce charts on the Mercator\u00a0projection. This projection is still the most widely used.\u00a0Sailing Directions or pilots have existed since at least\u00a0the 6th century B.C. Continuous accumulation of navigational\u00a0data, along with increased exploration and trade, led\u00a0to increased production of volumes through the Middle\u00a0Ages. <img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1396\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1370\/img_3555#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3555.jpg\" data-orig-size=\"2048,1536\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;2.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 3GS&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1403786064&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;3.85&quot;,&quot;iso&quot;:&quot;1000&quot;,&quot;shutter_speed&quot;:&quot;0.1&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"IMG_3555\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3555-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3555-1024x768.jpg\" class=\"size-medium wp-image-1396 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3555-300x225.jpg\" alt=\"IMG_3555\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3555-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3555-1024x768.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/07\/IMG_3555.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>\u201cRoutiers\u201d were produced in France about 1500; the\u00a0English referred to them as \u201crutters.\u201d In 1584 Lucas\u00a0Waghenaer published the Spieghel der Zeevaerdt (The\u00a0Mariner\u2019s Mirror), which became the model for such\u00a0publications for several generations of navigators. They\u00a0were known as \u201cWaggoners\u201d by most sailors.\u00a0The compass was developed about 1000 years ago.&lt;\/p&gt;<\/p>\n<p>Table 102. The relationship of the types and phases of navigation. * With SA off and\/or using DGPS The origin of the magnetic compass is uncertain, but Norsemen used it in the 11th century, and Chinese navigators used the magnetic compass at least that early and probably much earlier. It was not until the 1870s that Lord Kelvin developed a reliable dry card marine compass. The fluid-filled compass became standard in 1906. Variation was not understood until the 18th century, when Edmond Halley led an expedition to map lines of variation in the South Atlantic. Deviation was understood at least as early as the early 1600s, but adequate correction of compass error was not possible until Matthew Flinders discovered that a vertical iron bar could reduce certain types of errors. After 1840, British Astronomer Royal Sir George Airy and later Lord Kelvin developed combinations of iron masses and small magnets to eliminate most magnetic compass error. The gyrocompass was made necessary by iron and\u00a0steel ships. Leon Foucault developed the basic gyroscope in\u00a01852. An American (Elmer Sperry) and a German (Anshutz\u00a0Kampfe) both developed electrical gyrocompasses in the\u00a0early years of the 20th century. Ring laser gyrocompasses\u00a0and digital flux gate compasses are gradually replacing\u00a0traditional gyrocompasses, while the magnetic compass\u00a0remains an important backup device. <img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1553\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/100_1059#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1059.jpg\" data-orig-size=\"2592,4608\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;3.9&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1404185710&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.1&quot;,&quot;iso&quot;:&quot;250&quot;,&quot;shutter_speed&quot;:&quot;0.025&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_1059\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1059-168x300.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1059-576x1024.jpg\" class=\"size-medium wp-image-1553 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1059-168x300.jpg\" alt=\"100_1059\" width=\"168\" height=\"300\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1059-168x300.jpg 168w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1059-576x1024.jpg 576w\" sizes=\"auto, (max-width: 168px) 100vw, 168px\" \/>The log is the mariner\u2019s speedometer. Mariners originally measured speed by observing a chip of wood passing down the side of the vessel. Later developments included a wooden board attached to a reel of line. Mariners measured speed by noting how many knots in the line unreeled as the ship moved a measured amount of time; hence the term knot. Mechanical logs using either a small paddle wheel or a rotating spinner arrived about the middle of the 17th century. The taffrail log still in limited use today was developed in 1878. Modern logs use electronic sensors or spinning devices that induce small electric fields proportional to a vessel\u2019s speed. An engine revolution counter or shaft log often measures speed aboard large ships. Doppler speed logs are used on some vessels for very accurate speed readings. Inertial and satellite systems also provide highly accurate speed readings. The Metric Conversion Act of 1975 and the Omnibus Trade and Competitiveness Act of 1988 established the metric system of weights and measures in the United States. As a result, the government is converting charts to the metric format. Notwithstanding the conversion to the\u00a0metric system, the common measure of distance at sea is the nautical mile. The current policy of the National Imagery and Mapping Agency (NIMA) and the National Ocean Service (NOS) is to convert new compilations of nautical, special purpose charts, and publications to the metric system. All digital charts use the metric system. This conversion began on January 2, 1970. Most modern maritime nations have also adopted the meter as the standard measure of depths and heights. However, older charts still on issue and the charts of some foreign countries may not conform to this standard. The fathom as a unit of length or depth is of obscure origin. Posidonius reported a sounding of more than 1,000 fathoms in the 2nd century B.C. How old the unit was then is unknown. Many modern charts are still based on the fathom, as conversion to the metric system continues. The sailings refer to various methods of mathematically determining course, distance, and position. They have a history almost as old as mathematics itself. Thales, Hipparchus, Napier, Wright, and others contributed the formulas that permit computation of course and distance by plane, traverse, parallel, middle latitude, Mercator, and great circle sailings.<\/p>\n<h3>104. The Earth<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1753\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/dsc_2835#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/DSC_2835.jpg\" data-orig-size=\"3872,2592\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;5&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;NIKON 1 J1&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1403768751&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;22.7&quot;,&quot;iso&quot;:&quot;100&quot;,&quot;shutter_speed&quot;:&quot;0.0025&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"DSC_2835\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/DSC_2835-300x200.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/DSC_2835-1024x685.jpg\" class=\"size-medium wp-image-1753 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/DSC_2835-300x200.jpg\" alt=\"DSC_2835\" width=\"300\" height=\"200\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/DSC_2835-300x200.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/DSC_2835-1024x685.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>The Earth is an irregular oblate spheroid (a sphere\u00a0flattened at the poles). Measurements of its dimensions and\u00a0the amount of its flattening are subjects of geodesy.\u00a0However, for most navigational purposes, assuming a\u00a0spherical Earth introduces insignificant error. The Earth\u2019s\u00a0axis of rotation is the line connecting the north and south\u00a0geographic poles. A great circle is the line of intersection of a sphere and\u00a0a plane through its center. This is the largest circle that can\u00a0be drawn on a sphere. The shortest line on the surface of a\u00a0sphere between two points on the surface is part of a great\u00a0circle. On the spheroidal Earth the shortest line is called a\u00a0geodesic. A great circle is a near enough approximation to\u00a0Figure 104a. The planes of the meridians at the polar axis.\u00a0a geodesic for most problems of navigation. A small circle\u00a0is the line of intersection of a sphere and a plane which does\u00a0not pass through the center. See Figure 104a.\u00a0The term meridian is usually applied to the upper\u00a0branch of the half-circle from pole to pole which passes\u00a0through a given point. The opposite half is called the lower\u00a0branch. A parallel or parallel of latitude is a circle on the\u00a0surface of the Earth parallel to the plane of the equator.\u00a0It connects all points of equal latitude. The equator is a\u00a0great circle at latitude 0\u00b0. See Figure 104b. The poles are\u00a0single points at latitude 90\u00b0. All other parallels are small\u00a0circles.<\/p>\n<h3>105. Coordinates<\/h3>\n<div id=\"attachment_1741\" style=\"width: 306px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1741\" data-attachment-id=\"1741\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/img_3547#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3547.jpg\" data-orig-size=\"2048,1536\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;2.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 3GS&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1403785810&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;3.85&quot;,&quot;iso&quot;:&quot;500&quot;,&quot;shutter_speed&quot;:&quot;0.058823529411765&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Reflecting Circle\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;The Reflecting Circle (18th Century) was also called the Gunwale Circle. It was used to find the longitude by measuring the horizontal angle between the moon and the stars of the zodiac.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3547-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3547-1024x768.jpg\" class=\"size-medium wp-image-1741\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3547-300x225.jpg\" alt=\"The Reflecting Circle (18th Century) was also called the Gunwale Circle. It was used to find the longitude by measuring the horizontal angle between the moon and the stars of the zodiac.\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3547-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3547-1024x768.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3547.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><p id=\"caption-attachment-1741\" class=\"wp-caption-text\">The Reflecting Circle (18th Century) was also called the Gunwale Circle. It was used to find the longitude by measuring the horizontal angle between the moon and the stars of the zodiac.<\/p><\/div>\n<p>Coordinates of latitude and longitude can define any\u00a0position on Earth. Latitude (L, lat.) is the angular distance\u00a0from the equator, measured northward or southward along\u00a0a meridian from 0\u00b0 at the equator to 90\u00b0 at the poles. It is\u00a0designated north (N) or south (S) to indicate the direction of\u00a0measurement.The difference of latitude (l, DLat.) between two\u00a0places is the angular length of arc of any meridian between\u00a0their parallels. It is the numerical difference of the latitudes\u00a0if the places are on the same side of the equator; it is the sum\u00a0of the latitudes if the places are on opposite sides of the\u00a0equator. It may be designated north (N) or south (S) when\u00a0appropriate. The middle or mid-latitude (Lm) between\u00a0two places on the same side of the equator is half the sum\u00a0of their latitudes. Mid-latitude is labeled N or S to indicate\u00a0whether it is north or south of the equator.\u00a0The expression may refer to the mid-latitude of two\u00a0places on opposite sides of the equator. In this case, it is\u00a0equal to half the difference between the two latitudes and\u00a0takes the name of the place farthest from the equator.\u00a0Longitude (l, long.) is the angular distance between\u00a0the prime meridian and the meridian of a point on the Earth,\u00a0measured eastward or westward from the prime meridian\u00a0through 180\u00b0. It is designated east (E) or west (W) to\u00a0indicate the direction of measurement.\u00a0The difference of longitude (DLo) between two\u00a0places is the shorter arc of the parallel or the smaller angle\u00a0at the pole between the meridians of the two places. If both\u00a0places are on the same side (east or west) of Greenwich,\u00a0DLo is the numerical difference of the longitudes of the two\u00a0places; if on opposite sides, DLo is the numerical sum\u00a0unless this exceeds 180\u00b0, when it is 360\u00b0 minus the sum.\u00a0The distance between two meridians at any parallel of\u00a0latitude, expressed in distance units, usually nautical miles,\u00a0is called departure (p, Dep.). It represents distance made\u00a0good east or west as a craft proceeds from one point to\u00a0another. Its numerical value between any two meridians\u00a0decreases with increased latitude, while DLo is numerically\u00a0the same at any latitude. Either DLo or p may be designated\u00a0east (E) or west (W) when appropriate.<\/p>\n<h3>106. Distance on the Earth<\/h3>\n<p>al angle between the moon and the stars of the zodiac.<\/p>\n<div id=\"attachment_1748\" style=\"width: 231px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1748\" data-attachment-id=\"1748\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/img_3693#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3693.jpg\" data-orig-size=\"1229,1638\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;2.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 3GS&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1404041932&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;3.85&quot;,&quot;iso&quot;:&quot;500&quot;,&quot;shutter_speed&quot;:&quot;0.066666666666667&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"World Divided\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;Spain and Portugal division of World&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3693-225x300.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3693-768x1024.jpg\" class=\"size-medium wp-image-1748\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3693-225x300.jpg\" alt=\"Spain and Portugal division of World\" width=\"225\" height=\"300\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3693-225x300.jpg 225w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3693-768x1024.jpg 768w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3693.jpg 1229w\" sizes=\"auto, (max-width: 225px) 100vw, 225px\" \/><p id=\"caption-attachment-1748\" class=\"wp-caption-text\">Spain and Portugal division of World<\/p><\/div>\n<p>Distance, as used by the navigator, is the length of the\u00a0rhumb line connecting two places. This is a line making\u00a0the same angle with all meridians. Meridians and parallels\u00a0which also maintain constant true directions may be considered\u00a0special cases of the rhumb line. Any other rhumb\u00a0line spirals toward the pole, forming a loxodromic curve\u00a0or loxodrome. See Figure 106. Figure 104b. The equator is a great circle midway\u00a0between the poles. Figure 106. A loxodrome. Distance along the great circle connecting two points is customarily designated great-circle distance. For most purposes, considering the\u00a0nautical mile the length of one minute of latitude introduces\u00a0no significant error. \u00a0Speed (S) is rate of motion, or distance per unit of time.A knot (kn.), the unit of speed commonly used in\u00a0navigation, is a rate of 1 nautical mile per hour. The\u00a0expression speed of advance (SOA) is used to indicate the\u00a0speed to be made along the intended track. Speed over the\u00a0ground (SOG) is the actual speed of the vessel over the\u00a0surface of the Earth at any given time. To calculate speed\u00a0made good (SMG) between two positions, divide the\u00a0distance between the two positions by the time elapsed\u00a0between the two positions.<\/p>\n<h3>107. Direction on the Earth<\/h3>\n<p>Direction is the position of one point relative to\u00a0another. Navigators express direction as the angular\u00a0difference in degrees from a reference direction, usually\u00a0north or the ship\u2019s head. Course (C, Cn) is the horizontal\u00a0direction in which a vessel is intended to be steered,\u00a0expressed as angular distance from north clockwise through\u00a0360\u00b0. Strictly used, the term applies to direction through the\u00a0water, not the direction intended to be made good over the\u00a0ground.The course is often designated as true, magnetic,\u00a0compass, or grid according to the reference direction.\u00a0Track made good (TMG) is the single resultant\u00a0direction from the point of departure to point of arrival at\u00a0any given time. Course of advance (COA) is the direction\u00a0intended to be made good over the ground, and course over\u00a0ground (COG) is the direction between a vessel\u2019s last fix\u00a0and an EP. A course line is a line drawn on a chart\u00a0extending in the direction of a course. It is sometimes\u00a0convenient to express a course as an angle from either north\u00a0or south, through 90\u00b0 or 180\u00b0. In this case it is designated\u00a0course angle (C) and should be properly labeled to indicate\u00a0the origin (prefix) and direction of measurement (suffix).\u00a0Thus, C N35\u00b0E = Cn 035\u00b0 (000\u00b0 + 35\u00b0), C N155\u00b0W = Cn\u00a0205\u00b0 (360\u00b0 &#8211; 155\u00b0), C S47\u00b0E = Cn 133\u00b0 (180\u00b0 &#8211; 47\u00b0). But Cn\u00a0260\u00b0 may be either C N100\u00b0W or C S80\u00b0W, depending\u00a0upon the conditions of the problem.\u00a0Track (TR) is the intended horizontal direction of travel\u00a0with respect to the Earth. The terms intended track and\u00a0trackline are used to indicate the path of intended travel. See\u00a0Figure 107a. The track consists of one or a series of course\u00a0lines, from the point of departure to the destination, along\u00a0which one intends to proceed. A great circle which a vessel\u00a0intends to follow is called a great-circle track, though it\u00a0consists of a series of straight lines approximating a great circle\u00a0Heading (Hdg., SH) is the direction in which a vessel\u00a0is pointed at any given moment, expressed as angular\u00a0distance from 000\u00b0 clockwise through 360\u00b0. It is easy to\u00a0confuse heading and course. Heading constantly changes as\u00a0a vessel yaws back and forth across the course due to sea,\u00a0wind, and steering error.\u00a0Bearing (B, Brg.) is the direction of one terrestrial\u00a0point from another, expressed as angular distance from\u00a0000\u00b0 (North) clockwise through 360\u00b0. When measured\u00a0through 90\u00b0 or 180\u00b0 from either north or south, it is called\u00a0bearing angle (B). Bearing and azimuth are sometimes used\u00a0interchangeably, but the latter more accurately refers to the\u00a0horizontal direction of a point on the celestial sphere from\u00a0a point on the Earth. A relative bearing is measured relative\u00a0to the ship\u2019s heading from 000\u00b0 (dead ahead) clockwise\u00a0through 360\u00b0. However, it is sometimes conveniently measured\u00a0right or left from 000\u00b0 at the ship\u2019s head through\u00a0180\u00b0. This is particularly true when using the table for Distance of an Object by Two Bearings.\u00a0Figure 107a. Course line, track, track made good, and heading. To convert a relative bearing to a true bearing, add the true heading. See Figure 107b True Bearing = Relative Bearing + True Heading. Relative Bearing = True Bearing &#8211; True Heading.<\/p>\n<h3>108. Finding Latitude and Longitude<\/h3>\n<div id=\"attachment_1726\" style=\"width: 306px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1726\" data-attachment-id=\"1726\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/img_3533#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3533.jpg\" data-orig-size=\"2048,1536\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;2.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 3GS&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1403785415&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;3.85&quot;,&quot;iso&quot;:&quot;800&quot;,&quot;shutter_speed&quot;:&quot;0.1&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"IMG_3533\" data-image-description=\"&lt;p&gt;Recovered from the seabed in the vicinity of Ericeira, off the Portuguese Coast. Manufactured around 1600.&lt;\/p&gt;\n\" data-image-caption=\"&lt;p&gt;THe Ericeira Astrolabe&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3533-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3533-1024x768.jpg\" class=\"size-medium wp-image-1726\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3533-300x225.jpg\" alt=\"Astrolabe\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3533-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3533-1024x768.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3533.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><p id=\"caption-attachment-1726\" class=\"wp-caption-text\">THe Ericeira Astrolabe<\/p><\/div>\n<p>Navigators have made latitude observations for\u00a0thousands of years. Accurate declination tables for the Sun\u00a0have been published for centuries, enabling ancient seamen\u00a0to compute latitude to within 1 or 2 degrees. Those who\u00a0today determine their latitude by measuring the Sun at their\u00a0meridian and the altitude of Polaris are using methods well known to 15th century navigators. A method of finding longitude eluded mariners for\u00a0centuries. Several solutions independent of time proved too\u00a0cumbersome. Finding longitude by magnetic variation was\u00a0tried, but found too inaccurate. The lunar distance method,\u00a0which determines GMT by observing the Moon\u2019s position\u00a0among the stars, became popular in the 1800s. However,\u00a0the mathematics required by most of these processes were\u00a0far above the abilities of the average seaman. It was\u00a0apparent that the solution lay in keeping accurate time at\u00a0sea.<\/p>\n<div id=\"attachment_1729\" style=\"width: 306px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1729\" data-attachment-id=\"1729\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/img_3577#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3577.jpg\" data-orig-size=\"2048,1536\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;2.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 3GS&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1403788542&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;3.85&quot;,&quot;iso&quot;:&quot;100&quot;,&quot;shutter_speed&quot;:&quot;0.066666666666667&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"IMG_3577\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;lunar eclipses, lunar distances, the satellites of Jupiter, and other solutions to the longitude problem had been proposed besides the marine chronometer.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3577-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3577-1024x768.jpg\" class=\"size-medium wp-image-1729\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3577-300x225.jpg\" alt=\"lunar eclipses, lunar distances, the satellites of Jupiter, and other solutions to the longitude problem had been proposed besides the marine chronometer.\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3577-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3577-1024x768.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3577.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><p id=\"caption-attachment-1729\" class=\"wp-caption-text\">lunar eclipses, lunar distances, the satellites of Jupiter, and other solutions to the longitude problem had been proposed besides the marine chronometer.<\/p><\/div>\n<p>In 1714, the British Board of Longitude was formed, offering a small fortune in reward to anyone who could provide a solution to the problem. An Englishman, John Harrison, responded to the challenge, developing four chronometers between 1735 and 1760. The most accurate of these timepieces lost only 15 seconds on a 156 day round trip between London and Barbados. The Board, however, paid him only half the promised reward. The King finally intervened on Harrison\u2019s behalf, and at the age of 80 years Harrison received his full reward of \u00a320,000. Rapid chronometer development led to the problem of\u00a0determining chronometer error aboard ship. Time balls,\u00a0large black spheres mounted in port in prominent locations,\u00a0were dropped at the stroke of noon, enabling any ship in\u00a0harbor which could see the ball to determine chronometer\u00a0error. By the end of the U.S. Civil War, telegraph signals\u00a0were being used to key time balls. Use of radio signals to\u00a0send time ticks to ships well offshore began in 1904, and\u00a0soon worldwide signals were available.<\/p>\n<h3>109. The Navigational Triangle<\/h3>\n<p>Modern celestial navigators reduce their celestial\u00a0observations by solving a navigational triangle whose\u00a0points are the elevated pole, the celestial body, and the\u00a0zenith of the observer. The sides of this triangle are the polar\u00a0distance of the body (codeclination), its zenith distance\u00a0(coaltitude), and the polar distance of the zenith (colatitude\u00a0of the observer). A spherical triangle was first used at sea in solving\u00a0lunar distance problems. Simultaneous observations were\u00a0made of the altitudes of the Moon and the Sun or a star near\u00a0the ecliptic and the angular distance between the Moon and\u00a0the other body. The zenith of the observer and the two\u00a0celestial bodies formed the vertices of a triangle whose\u00a0sides were the two coaltitudes and the angular distance\u00a0between the bodies. Using a mathematical calculation the\u00a0navigator \u201ccleared\u201d this distance of the effects of refraction\u00a0and parallax applicable to each altitude. This corrected\u00a0value was then used as an argument for entering the\u00a0almanac. The almanac gave the true lunar distance from the\u00a0Sun and several stars at 3 hour intervals. Previously, the Figure 107b. Relative Bearing navigator had set his watch or checked its error and rate\u00a0with the local mean time determined by celestial\u00a0observations. The local mean time of the watch, properly\u00a0corrected, applied to the Greenwich mean time obtained\u00a0from the lunar distance observation, gave the longitude.\u00a0The calculations involved were tedious. Few mariners\u00a0could solve the triangle until Nathaniel Bowditch published\u00a0his simplified method in 1802 in The New American\u00a0Practical Navigator. Reliable chronometers were available by1800, but their\u00a0high cost precluded their general use aboard most ships.\u00a0However, most navigators could determine their longitude\u00a0using Bowditch\u2019s method. This eliminated the need for\u00a0parallel sailing and the lost time associated with it. Tables for\u00a0the lunar distance solution were carried in the American\u00a0nautical almanac into the 20th century.<\/p>\n<h3>110. The Time Sight<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1724\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/img_3579#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3579.jpg\" data-orig-size=\"2048,1536\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;2.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;iPhone 3GS&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1403788633&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;3.85&quot;,&quot;iso&quot;:&quot;200&quot;,&quot;shutter_speed&quot;:&quot;0.066666666666667&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"IMG_3579\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3579-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3579-1024x768.jpg\" class=\"size-medium wp-image-1724 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3579-300x225.jpg\" alt=\"IMG_3579\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3579-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3579-1024x768.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/IMG_3579.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>The theory of the time sight had been known to mathematicians\u00a0since the development of spherical trigonometry,\u00a0but not until the chronometer was developed could it be used\u00a0by mariners. The time sight used the modern navigational triangle. The codeclination, or polar distance, of the body could be determined from the almanac. The zenith distance\u00a0(coaltitude) was determined by observation. If the\u00a0colatitude were known, three sides of the triangle were available. From these the meridian angle was computed.\u00a0The comparison of this with the Greenwich hour angle from\u00a0the almanac yielded the longitude.<br \/>\nThe time sight was mathematically sound, but the navigator\u00a0was not always aware that the longitude determined was only as\u00a0accurate as the latitude, and together they merely formed a point\u00a0on what is known today as a line of position.<img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1503\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/100_1011#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1011.jpg\" data-orig-size=\"4608,2592\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;10.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1404125566&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.1&quot;,&quot;iso&quot;:&quot;64&quot;,&quot;shutter_speed&quot;:&quot;0.008&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_1011\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1011-300x168.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1011-1024x576.jpg\" class=\"size-medium wp-image-1503 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1011-300x168.jpg\" alt=\"100_1011\" width=\"300\" height=\"168\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1011-300x168.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1011-1024x576.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/> If the observed\u00a0body was on the prime vertical, the line of position ran north and\u00a0south and a small error in latitude generally had little effect on\u00a0the longitude. But when the body was close to the meridian, a\u00a0small error in latitude produced a large error in longitude.\u00a0Figure 110. The first celestial line of position, obtained by Captain Thomas Sumner in1837. The line of position by celestial observation was unknown\u00a0until discovered in 1837 by 30-year-old Captain\u00a0Thomas H. Sumner, a Harvard graduate and son of a United\u00a0States congressman from Massachusetts. The discovery of\u00a0the \u201cSumner line,\u201d as it is sometimes called, was considered\u00a0by Maury \u201cthe commencement of a new era in practical\u00a0navigation.\u201d This was the turning point in the development\u00a0of modern celestial navigation technique. In Sumner\u2019s own\u00a0words, the discovery took place in this manner:<\/p>\n<blockquote><p>Having sailed from Charleston, S. C., 25th November,\u00a01837, bound to Greenock, a series of heavy gales\u00a0from the Westward promised a quick passage; after passing\u00a0the Azores, the wind prevailed from the Southward,\u00a0with thick weather; after passing Longitude 21\u00b0 W, no observation\u00a0was had until near the land; but soundings were\u00a0had not far, as was supposed, from the edge of the Bank.\u00a0The weather was now more boisterous, and very thick;\u00a0and the wind still Southerly; arriving about midnight,\u00a017th December, within 40 miles, by dead reckoning, of\u00a0Tusker light; the wind hauled SE, true, making the Irish\u00a0coast a lee shore; the ship was then kept close to the wind,\u00a0and several tacks made to preserve her position as nearly\u00a0as possible until daylight; when nothing being in sight,\u00a0she was kept on ENE under short sail, with heavy gales;\u00a0at about 10 AM an altitude of the Sun was observed, and\u00a0the Chronometer time noted; but, having run so far without\u00a0any observation, it was plain the Latitude by dead\u00a0reckoning was liable to error, and could not be entirely\u00a0relied on. Using, however, this Latitude, in finding the\u00a0Longitude by Chronometer, it was found to put the ship\u00a015&#8242; of Longitude E from her position by dead reckoning;\u00a0which in Latitude 52\u00b0Nis 9 nautical miles; this seemed to\u00a0agree tolerably well with the dead reckoning; but feeling\u00a0doubtful of the Latitude, the observation was tried with a\u00a0Latitude 10&#8242; further N, finding this placed the ship ENE\u00a027 nautical miles, of the former position, it was tried\u00a0again with a Latitude 20&#8242; N of the dead reckoning; this\u00a0also placed the ship still further ENE, and still 27 nautical\u00a0miles further; these three positions were then seen to lie\u00a0in the direction of Small\u2019s light. It then at once appeared\u00a0that the observed altitude must have happened at all\u00a0the three points, and at Small\u2019s light, and at the ship,\u00a0at the same instant of time; and it followed, that\u00a0Small\u2019s light must bear ENE, if the Chronometer\u00a0was right. Having been convinced of this truth, the\u00a0ship was kept on her course, ENE, the wind being still\u00a0SE., and in less than an hour, Small\u2019s light was made\u00a0bearing ENE 1\/2 E, and close aboard.<\/p><\/blockquote>\n<p>In 1843 Sumner published a book, A New and Accurate\u00a0Method of Finding a Ship\u2019s Position at Sea by Projection\u00a0on Mercator\u2019s Chart. He proposed solving a single time\u00a0sight twice, using latitudes somewhat greater and somewhat\u00a0less than that arrived at by dead reckoning, and joining the\u00a0two positions obtained to form the line of position.\u00a0The Sumner method required the solution of two time\u00a0sights to obtain each line of position. Many older navigators\u00a0preferred not to draw the lines on their charts, but to fix\u00a0their position mathematically by a method which Sumner\u00a0had also devised and included in his book. This was a tedious\u00a0but popular procedure.<\/p>\n<h3>111. Navigational Tables<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1551\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/100_0966#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0966.jpg\" data-orig-size=\"4608,2592\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;3.9&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1404099794&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.1&quot;,&quot;iso&quot;:&quot;100&quot;,&quot;shutter_speed&quot;:&quot;0.025&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_0966\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0966-300x168.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0966-1024x576.jpg\" class=\"size-medium wp-image-1551 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0966-300x168.jpg\" alt=\"100_0966\" width=\"300\" height=\"168\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0966-300x168.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0966-1024x576.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>Spherical trigonometry is the basis for solving every\u00a0navigational triangle, and until about 80 years ago the\u00a0navigator had no choice but to solve each triangle by\u00a0tedious, manual computations.\u00a0Lord Kelvin, generally considered the father of modern\u00a0navigational methods, expressed interest in a book of tables with\u00a0which a navigator could avoid tedious trigonometric solutions.\u00a0However, solving the many thousands of triangles involved\u00a0would have made the project too costly. Computers finally\u00a0provided a practical means of preparing tables. In 1936 the first\u00a0<span style=\"font-size: 13px;\">volume of Pub. No. 214 was made available; later, Pub. No. 249\u00a0<\/span><span style=\"font-size: 13px;\">was provided for air navigators. Pub. No. 229, Sight Reduction<\/span> Tables for Marine Navigation, has replaced Pub. No. 214.\u00a0Electronic calculators are gradually replacing the\u00a0tables. Scientific calculators with trigonometric functions\u00a0can easily solve the navigational triangle. Navigational\u00a0calculators readily solve celestial sights and perform a\u00a0variety of voyage planning functions. Using a calculator\u00a0generally gives more accurate lines of position because it\u00a0eliminates the rounding errors inherent in tabular inspection\u00a0and interpolation.<\/p>\n<h3>112. Development of Electronic Navigation<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1550\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/100_0965#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0965.jpg\" data-orig-size=\"4608,2592\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;3.9&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1404099781&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.1&quot;,&quot;iso&quot;:&quot;100&quot;,&quot;shutter_speed&quot;:&quot;0.025&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_0965\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0965-300x168.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0965-1024x576.jpg\" class=\"size-medium wp-image-1550 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0965-300x168.jpg\" alt=\"100_0965\" width=\"300\" height=\"168\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0965-300x168.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_0965-1024x576.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>Perhaps the first application of electronics to\u00a0navigation involved sending telegraphic time signals in\u00a01865 to check chronometer error. Transmitting radio time\u00a0signals for chronometer checks dates to 1904. Radio\u00a0broadcasts providing navigational warnings, begun in 1907\u00a0by the U.S. Navy Hydrographic Office, helped increase the\u00a0safety of navigation at sea. By the latter part of World War I the directional\u00a0properties of a loop antenna were successfully used in the\u00a0radio direction finder. The first radiobeacon was installed in\u00a01921. Early 20th century experiments by Behm and\u00a0Langevin led to the U.S. Navy\u2019s development of the first\u00a0practical echo sounder in 1922. Radar and hyperbolic\u00a0systems grew out of WWII. Today, electronics touches almost every aspect of\u00a0navigation. Hyperbolic systems, satellite systems, and\u00a0electronic charts all require an increasingly sophisticated\u00a0electronics suite and the expertise to manage them. These\u00a0systems\u2019 accuracy and ease of use make them invaluable\u00a0assets to the navigator, but there is far more to using them\u00a0than knowing which buttons to push.<\/p>\n<h3>113. Development of Radar<\/h3>\n<p>As early as 1904, German engineers were experimenting\u00a0with reflected radio waves. In 1922 two American scientists,\u00a0Dr. A. Hoyt Taylor and Leo C. Young, testing a communication\u00a0system at the Naval Aircraft Radio Laboratory, noted\u00a0fluctuations in the signals when ships passed between stations\u00a0on opposite sides of the Potomac River. In 1935 the British\u00a0began work on radar. In 1937 the USS Leary tested the first\u00a0sea-going radar, and in 1940 United States and British\u00a0scientists combined their efforts. When the British revealed the\u00a0principle of the multicavity magnetron developed by J. T.\u00a0Randall and H. A. H. Boot at the University of Birmingham in\u00a01939, microwave radar became practical. In 1945, at the close\u00a0of World War II, radar became available for commercial use.<\/p>\n<h3>114. Development of Hyperbolic Radio Aids<\/h3>\n<p>Various hyperbolic systems were developed beginning\u00a0in World War II. These were outgrowths of the British GEE\u00a0system, developed to help bombers navigate to and from\u00a0their missions over Europe. Loran A was developed as a\u00a0long-range marine navigation system. This was replaced by\u00a0the more accurate Loran C system, deployed throughout\u00a0much of the world. Various short range and regional\u00a0hyperbolic systems have been developed by private\u00a0industry for hydrographic surveying, offshore facilities\u00a0positioning, and general navigation.<\/p>\n<h3>115. Other Electronic Systems<\/h3>\n<p>The underlying concept that led to development of\u00a0satellite navigation dates to 1957 and the first launch of an\u00a0artificial satellite into orbit. The first system, NAVSAT, has\u00a0been replaced by the far more accurate and widely available\u00a0Global Positioning System (GPS), which has revolutionized\u00a0all aspects of navigation <img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1509\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1493\/image-9#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image.jpg\" data-orig-size=\"2048,1536\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image-1024x768.jpg\" class=\"size-medium wp-image-1509 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image-300x225.jpg\" alt=\"image\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image-1024x768.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>The first inertial navigation system was developed in\u00a01942 for use in the V2 missile by the Peenemunde group under\u00a0the leadership of Dr. Wernher von Braun. This system used two\u00a02-degree-of-freedom gyroscopes and an integrating accelerometer\u00a0to determine the missile velocity. By the end of World\u00a0War II, the Peenemunde group had developed a stable platform\u00a0with three single-degree-of-freedom gyroscopes and an\u00a0integrating accelerometer. In 1958 an inertial navigation system\u00a0was used to navigate the USS Nautilus under the ice to the\u00a0North Pole.<\/p>\n<h3>116. Governmental Role<\/h3>\n<div id=\"attachment_1579\" style=\"width: 306px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1579\" data-attachment-id=\"1579\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1493\/image-14#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image5.jpg\" data-orig-size=\"2048,1536\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Baptismal Fount\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;US Navy Bells, following English tradition are still used (inverted) as baptismal founts. Names of the Baptized are inscribed inside the bell.&lt;\/p&gt;\n\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image5-300x225.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image5-1024x768.jpg\" class=\"size-medium wp-image-1579\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image5-300x225.jpg\" alt=\"US Navy Bells, following English tradition are still used (inverted) as baptismal founts. Names of the Baptized are inscribed inside the bell.\" width=\"300\" height=\"225\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image5-300x225.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image5-1024x768.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image5.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><p id=\"caption-attachment-1579\" class=\"wp-caption-text\">US Navy Bells, following English tradition are still used (inverted) as baptismal founts. Names of the Baptized are inscribed inside the bell.<\/p><\/div>\n<p>Navigation only a generation ago was an independent\u00a0process, carried out by the mariner without outside\u00a0assistance. With compass and charts, sextant and\u00a0chronometer, he could independently travel anywhere in\u00a0the world. The increasing use of electronic navigation\u00a0systems has made the navigator dependent on many factors\u00a0outside his control. Government organizations fund,\u00a0operate, and regulate satellites, Loran, and other electronic\u00a0systems. Governments are increasingly involved in\u00a0regulation of vessel movements through traffic control\u00a0systems and regulated areas. Understanding the governmental\u00a0role in supporting and regulating navigation is\u00a0vitally important to the mariner. In the United States, there\u00a0are a number of official organizations which support the\u00a0interests of navigators. Some have a policy-making role;\u00a0others build and operate navigation systems. Many\u00a0maritime nations have similar organizations performing\u00a0similar functions. International organizations also play a\u00a0significant role.<\/p>\n<h3>117. The Coast and Geodetic Survey<\/h3>\n<p>The U.S. Coast and Geodetic Survey was founded in\u00a01807 when Congress passed a resolution authorizing a\u00a0survey of the coast, harbors, outlying islands, and fishing\u00a0banks of the United States. President Thomas Jefferson\u00a0appointed Ferdinand Hassler, a Swiss immigrant and\u00a0professor of mathematics at West Point, the first Director of\u00a0the \u201cSurvey of the Coast.\u201d The survey became the \u201cCoast\u00a0Survey\u201d in 1836. The approaches to New York were the first sections of\u00a0the coast charted, and from there the work spread northward\u00a0and southward along the eastern seaboard. In 1844 the work\u00a0was expanded and arrangements made to simultaneously\u00a0chart the gulf and east coasts. Investigation of tidal\u00a0conditions began, and in 1855 the first tables of tide\u00a0predictions were published. The California gold rush\u00a0necessitated a survey of the west coast, which began in\u00a01850, the year California became a state. Coast Pilots, or\u00a0Sailing Directions, for the Atlantic coast of the United\u00a0States were privately published in the first half of the 19th\u00a0century. In 1850 the Survey began accumulating data that\u00a0led to federally produced Coast Pilots. The 1889 Pacific\u00a0Coast Pilot was an outstanding contribution to the safety of\u00a0west coast shipping.&lt;p&gt; In 1878 the survey was renamed \u201cCoast and Geodetic\u00a0Survey.\u201d In 1970 the survey became the \u201cNational Ocean\u00a0Survey,\u201d and in 1983 it became the \u201cNational Ocean\u00a0Service.\u201d The Office of Charting and Geodetic Services\u00a0accomplished all charting and geodetic functions. In 1991\u00a0the name was changed back to the original \u201cCoast and\u00a0Geodetic Survey,\u201d organized under the National Ocean\u00a0Service along with several other environmental offices.\u00a0Today it provides the mariner with the charts and coast\u00a0pilots of all waters of the United States and its possessions,\u00a0and tide and tidal current tables for much of the world. Its\u00a0administrative order requires the Coast and Geodetic\u00a0Survey to plan and direct programs to produce charts and\u00a0related information for safe navigation of U.S. waterways,\u00a0territorial seas, and airspace. This work includes all\u00a0activities related to the National Geodetic Reference\u00a0System; surveying, charting, and data collection;\u00a0production and distribution of charts; and research and\u00a0development of new technologies to enhance these\u00a0missions.<\/p>\n<h3>118. The National Imagery and Mapping Agency<\/h3>\n<p>In the first years of the newly formed United States of\u00a0America, charts and instruments used by the Navy and\u00a0merchant mariners were left over from colonial days or\u00a0were obtained from European sources. In 1830 the U.S.\u00a0Navy established a \u201cDepot of Charts and Instruments\u201d in\u00a0Washington, D. C., as a storehouse from which available\u00a0charts, pilots and sailing directions, and navigational instruments were issued to Naval ships. Lieutenant L. M.\u00a0Goldsborough and one assistant, Passed Midshipman R. B.\u00a0Hitchcock, constituted the entire staff. The first chart published by the Depot was produced\u00a0from data obtained in a survey made by Lieutenant Charles\u00a0Wilkes, who had succeeded Goldsborough in 1834. Wilkes\u00a0later earned fame as the leader of a United States expedition\u00a0to Antarctica. From 1842 until 1861 Lieutenant Matthew\u00a0Fontaine Maury served as Officer in Charge. Under his\u00a0command the Depot rose to international prominence.\u00a0Maury decided upon an ambitious plan to increase the\u00a0mariner\u2019s knowledge of existing winds, weather, and\u00a0currents. He began by making a detailed record of pertinent\u00a0matter included in old log books stored at the Depot. He\u00a0then inaugurated a hydrographic reporting program among\u00a0ship masters, and the thousands of reports received, along\u00a0with the log book data, were compiled into the \u201cWind and\u00a0Current Chart of the North Atlantic\u201d in 1847. This is the\u00a0ancestor of today\u2019s Pilot Chart. The United States instigated an international\u00a0conference in 1853 to interest other nations in a system of\u00a0exchanging nautical information. The plan, which was\u00a0Maury\u2019s, was enthusiastically adopted by other maritime\u00a0nations. In 1854 the Depot was redesignated the \u201cU.S.\u00a0Naval Observatory and Hydrographical Office.\u201d At the\u00a0outbreak of the American Civil War in 1861, Maury, a\u00a0native of Virginia, resigned from the U.S. Navy and\u00a0accepted a commission in the Confederate Navy. This\u00a0effectively ended his career as a navigator, author, and\u00a0oceanographer. At war\u2019s end, he fled the country, his\u00a0reputation suffering from his embrace of the Confederate\u00a0cause. After Maury\u2019s return to the United States in 1868, he\u00a0served as an instructor at the Virginia Military Institute. He\u00a0continued at this position until his death in 1873. Since his\u00a0death, his reputation as one of America\u2019s greatest hydrographers\u00a0has been restored. In 1866 Congress separated the Observatory and the\u00a0Hydrographic Office, broadly increasing the functions of\u00a0the latter. The Hydrographic Office was authorized to carry\u00a0out surveys, collect information, and print every kind of\u00a0nautical chart and publication \u201cfor the benefit and use of\u00a0navigators generally.\u201d The Hydrographic Office purchased the copyright of\u00a0The New American Practical Navigator in 1867. The first\u00a0Notice to Mariners appeared in 1869. Daily broadcast of\u00a0navigational warnings was inaugurated in 1907. In 1912,\u00a0following the sinking of the Titanic, the International Ice\u00a0Patrol was established. In 1962 the U.S. Navy Hydrographic Office was\u00a0redesignated the U.S. Naval Oceanographic Office. In 1972\u00a0certain hydrographic functions of the latter office were\u00a0transferred to the Defense Mapping AgencyHydrographic Center. In 1978 the Defense Mapping\u00a0Agency Hydrographic\/Topographic Center\u00a0(DMAHTC) assumed hydrographic and topographic chart\u00a0production functions. In 1996 the National Imagery and\u00a0Mapping Agency (NIMA) was formed from DMA and\u00a0certain other elements of the Department of Defense.NIMA continues to produce charts and publications and to\u00a0disseminate maritime safety information in support of the\u00a0U.S. military and navigators generally. 119. The United States Coast Guard Alexander Hamilton established the U.S. Coast\u00a0Guard as the Revenue Marine, later the Revenue Cutter\u00a0Service, on August 4, 1790. It was charged with enforcing\u00a0the customs laws of the new nation. A revenue cutter, the\u00a0Harriet Lane, fired the first shot from a naval unit in the\u00a0Civil War at Fort Sumter. The Revenue Cutter Service\u00a0became the U.S. Coast Guard when combined with the\u00a0Lifesaving Service in 1915. The Lighthouse Service was\u00a0added in 1939, and the Bureau of Marine Inspection and\u00a0Navigation was added in 1942. The Coast Guard was\u00a0transferred from the Treasury Department to the\u00a0Department of Transportation in 1967. The primary functions of the Coast Guard include\u00a0maritime search and rescue, law enforcement, and\u00a0operation of the nation\u2019s aids to navigation system. In\u00a0addition, the Coast Guard is responsible for port safety and\u00a0security, merchant marine inspection, and marine pollution\u00a0control. The Coast Guard operates a large and varied fleet\u00a0of ships, boats, and aircraft in performing its widely ranging\u00a0duties Navigation systems operated by the Coast Guard\u00a0include the system of some 40,000 lighted and unlighted\u00a0beacons, buoys, and ranges in U.S. and territorial waters;\u00a0the U.S. stations of the Loran C system; differential GPS\u00a0(DGPS) services in the U.S.; and Vessel Traffic Services\u00a0(VTS) in major ports and harbors of the U.S.<\/p>\n<h3>120. The United States Navy<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1593\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1493\/image-10#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image1-e1407281581680.jpg\" data-orig-size=\"1536,2048\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image1-e1407281581680-225x300.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image1-e1407281581680-768x1024.jpg\" class=\"size-medium wp-image-1593 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image1-e1407281581680-225x300.jpg\" alt=\"image\" width=\"225\" height=\"300\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image1-e1407281581680-225x300.jpg 225w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image1-e1407281581680-768x1024.jpg 768w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/image1-e1407281581680.jpg 1536w\" sizes=\"auto, (max-width: 225px) 100vw, 225px\" \/>The U.S. Navy was officially established in 1798. Its\u00a0role in the development of navigational technology has been\u00a0singular. From the founding of the Naval Observatory to the\u00a0development of the most advanced electronics, the U.S.\u00a0Navy has been a leader in developing devices and techniques\u00a0designed to make the navigator\u2019s job safer and easier.\u00a0The development of almost every device known to\u00a0navigation science has been deeply influenced by Naval\u00a0policy. Some systems are direct outgrowths of specific\u00a0Naval needs; some are the result of technological\u00a0improvements shared with other services and with\u00a0commercial maritime industry.<\/p>\n<h3>121. The United States Naval Observatory<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"838\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1695\/image259#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/04\/Image259.jpg\" data-orig-size=\"1280,1024\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;6555b&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Image259\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/04\/Image259-300x240.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/04\/Image259-1024x819.jpg\" class=\"size-medium wp-image-838 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/04\/Image259-300x240.jpg\" alt=\"Image259\" width=\"300\" height=\"240\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/04\/Image259-300x240.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/04\/Image259-1024x819.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/04\/Image259.jpg 1280w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>One of the first observatories in the United States was\u00a0built in 1831-1832 at Chapel Hill, N.C. The Depot of Charts\u00a0and Instruments, established in 1830, was the agency from\u00a0which the U.S. Navy Hydrographic Office and the U.S.\u00a0Naval Observatory evolved 36 years later. In about 1835,\u00a0under Lieutenant Charles Wilkes, the second Officer in\u00a0Charge, the Depot installed a small transit instrument for\u00a0rating chronometers. The Mallory Act of 1842 provided for the\u00a0establishment of a permanent observatory. The director was\u00a0authorized to purchase everything necessary to continue\u00a0astronomical study. The observatory was completed in\u00a01844 and the results of its first observations were published\u00a0two years later. Congress established the Naval\u00a0Observatory as a separate agency in 1866. In 1873 a\u00a0refracting telescope with a 26 inch aperture, then the\u00a0world\u2019s largest, was installed. The observatory, located in\u00a0Washington, D.C., has occupied its present site since 1893.<\/p>\n<h3>122. The Royal Greenwich Observatory<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"834\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/sample-page\/image255#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image255.jpg\" data-orig-size=\"1280,1024\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;6555b&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Image255\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image255-300x240.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image255-1024x819.jpg\" class=\"size-medium wp-image-834 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image255-300x240.jpg\" alt=\"Image255\" width=\"300\" height=\"240\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image255-300x240.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image255-1024x819.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image255.jpg 1280w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>England had no early privately supported observatories such as those on the continent. The need for navigational advancement was ignored by Henry VIII and Elizabeth I, but in 1675 Charles II, at the urging of John Flamsteed, Jonas Moore, Le Sieur de Saint Pierre, and Christopher Wren, established the Greenwich Royal Observatory. Charles limited construction costs to \u00a3500, and appointed Flamsteed the first Astronomer Royal, at an annual salary of \u00a3100. The equipment available in the early years of the observatory consisted of two clocks, a \u201csextant\u201d of 7 foot radius, a quadrant of 3 foot radius, two telescopes, and the star catalog published almost a century before by Tycho Brahe. Thirteen years passed before Flamsteed had an instrument with which he could determine his latitude accurately. In 1690 a transit instrument equipped with a telescope and vernier was invented by Romer; he later added a vertical circle to the device. This enabled the astronomer to determine declination and right ascension at the same time. One of these instruments was added to the equipment at Greenwich in 1721, replacing the huge quadrant previously used. The development and perfection of the chronometer in the next hundred years added to the accuracy of observations. Other national observatories were constructed in the years that followed: at Berlin in 1705, St. Petersburg in 1725, Palermo in 1790, Cape of Good Hope in 1820, Parramatta in New South Wales in 1822, and Sydney in 1855.<\/p>\n<h3>123. The International Hydrographic Organization<\/h3>\n<p>The International Hydrographic Organization (IHO) was originally established in 1921 as the International Hydrographic Bureau (IHB). The present name was adopted in 1970 as a result of a revised international agreement among member nations. However, the former name, International Hydrographic Bureau, was retained for the IHO\u2019s administrative body of three Directors and their staff at the organization\u2019s headquarters in Monaco. The IHO sets forth hydrographic standards to be agreed upon by the member nations. All member states are urged and encouraged to follow these standards in their surveys, nautical charts, and publications. As these standards are uniformly adopted, the products of the world\u2019s hydrographic and oceanographic offices become more uniform. Much has been done in the field of standardization since the Bureau was founded. The principal work undertaken by the IHO is:<\/p>\n<ul>\n<li>To bring about a close and permanent association between national hydrographic offices.<\/li>\n<li>To study matters relating to hydrography and allied sciences and techniques.<\/li>\n<li>To further the exchange of nautical charts and documents between hydrographic offices of member governments.<\/li>\n<li>To circulate the appropriate documents.<\/li>\n<li>To tender guidance and advice upon request, in particular to countries engaged in setting up or expanding their hydrographic service.<\/li>\n<li>To encourage coordination of hydrographic surveys with relevant oceanographic activities.<\/li>\n<li>To extend and facilitate the application of oceanographic knowledge for the benefit of navigators.<\/li>\n<li>To cooperate with international organizations and scientific institutions which have related objectives.<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"835\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/sample-page\/image257#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image257.jpg\" data-orig-size=\"1280,1024\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;6555b&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Image257\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image257-300x240.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image257-1024x819.jpg\" class=\"size-medium wp-image-835 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image257-300x240.jpg\" alt=\"Image257\" width=\"300\" height=\"240\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image257-300x240.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image257-1024x819.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image257.jpg 1280w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>During the 19th century, many maritime nations established hydrographic offices to provide means for improving the navigation of naval and merchant vessels by providing nautical publications, nautical charts, and other navigational services. There were substantial differences in hydrographic procedures, charts, and publications. In 1889, an International Marine Conference was held at Washington, D. C., and it was proposed to establish a \u201cpermanent international commission.\u201d Similar proposals were made at the sessions of the International Congress of Navigation held at St. Petersburg in 1908 and again in 1912. In 1919 the hydrographers of Great Britain and France cooperated in taking the necessary steps to convene an international conference of hydrographers. London was selected as the most suitable place for this conference, and on July 24, 1919, the First International Conference opened, attended by the hydrographers of 24 nations. The object of the conference was \u201cTo consider the advisability of all maritime nations adopting similar methods in the preparation, construction, and production of their charts and all hydrographic publications; of rendering the results in the most convenient form to enable them to be readily used; of instituting a prompt system of mutual exchange of hydrographic information between all countries; and of providing an opportunity to consultations and discussions to be carried out on hydrographic subjects generally by the hydrographic experts of the world.\u201d This is still the major purpose of the International Hydrographic Organization. As a result of the conference, a permanent organization was formed and statutes for its operations were prepared. <img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"836\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/sample-page\/image258#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image258.jpg\" data-orig-size=\"1280,1024\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;6555b&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Image258\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image258-300x240.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image258-1024x819.jpg\" class=\"size-medium wp-image-836 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image258-300x240.jpg\" alt=\"Image258\" width=\"300\" height=\"240\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image258-300x240.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image258-1024x819.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image258.jpg 1280w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>The International Hydrographic Bureau, now the International Hydrographic Organization, began its activities in 1921 with 18 nations as members. The Principality of Monaco was selected because of its easy communication with the rest of the world and also because of the generous offer of Prince Albert I of Monaco to provide suitable accommodations for the Bureau in the Principality. There are currently 59 member governments. Technical assistance with hydrographic matters is available through the IHO to member states requiring it. Many IHO publications are available to the general public, such as the International Hydrographic Review, International Hydrographic Bulletin, Chart Specifications of the IHO, Hydrographic Dictionary, and others. Inquiries should be made to the International Hydrographic Bureau, 7 Avenue President J. F. Kennedy, B.P. 445, MC98011, Monaco, CEDEX. 124. The International Maritime Organization The International Maritime Organization (IMO) was established by United Nations Convention in 1948. The Convention actually entered into force in 1959, although an international convention on marine pollution was adopted in 1954. (Until 1982 the official name of the organization was the Inter-Governmental Maritime Consultative Organization.) It is the only permanent body of the U. N. devoted to maritime matters, and the only special U. N. agency to have its headquarters in the UK. The governing body of the IMO is the Assembly of 137 member states, which meets every two years. Between Assembly sessions a Council, consisting of 32 member governments elected by the Assembly, governs the organization. Its work is carried out by the Maritime Safety Committee, with subcommittees for:<\/p>\n<ul>\n<li>Safety of Navigation<\/li>\n<li>Radiocommunications<\/li>\n<li>Life-saving<\/li>\n<li>Search and Rescue<\/li>\n<li>Training and Watchkeeping<\/li>\n<li>Carriage of Dangerous Goods<\/li>\n<li>Ship Design and Equipment<\/li>\n<li>Fire Protection<\/li>\n<li>Stability and Load Lines\/Fishing Vessel Safety<\/li>\n<li>Containers and Cargoes<\/li>\n<li>Bulk Chemicals<\/li>\n<li>Marine Environment Protection Committee<\/li>\n<li>Legal Committee<\/li>\n<li>Technical Cooperation Committee<\/li>\n<li>Facilitation Committee<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"830\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/sample-page\/image250#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image250.jpg\" data-orig-size=\"1280,1024\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;6555b&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Image250\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image250-300x240.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image250-1024x819.jpg\" class=\"size-medium wp-image-830 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image250-300x240.jpg\" alt=\"Image250\" width=\"300\" height=\"240\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image250-300x240.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image250-1024x819.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image250.jpg 1280w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>IMO is headed by the Secretary General, appointed by the council and approved by the Assembly. He is assisted by some 300 civil servants. To achieve its objectives of coordinating international policy on marine matters, the IMO has adopted some 30 conventions and protocols, and adopted over 700 codes and recommendations. An issue to be adopted first is brought before a committee or subcommittee, which submits a draft to a conference. When the conference adopts the final text, it is submitted to member governments for ratification. Ratification by a specified number of countries is necessary for adoption; the more important the issue, the more countries must ratify. Adopted conventions are binding on member governments. Codes and recommendations are not binding, but in most cases are supported by domestic legislation by the governments involved. The first and most far-reaching convention adopted by the IMO was the Convention of Safety of Life at Sea (SOLAS) in 1960. This convention actually came into force in 1965, replacing a version first adopted in 1948. Because of the difficult process of bringing amendments into force internationally, none of subsequent amendments became binding. To remedy this situation, a new convention was adopted in 1974 and became binding in 1980. Among the regulations is V-20, requiring the carriage of up-to-date charts and publications sufficient for the intended voyage. Other conventions and amendments were also adopted, such as the International Convention on Load Lines (adopted 1966, came into force 1968), a convention on the tonnage measurement of ships (adopted 1969, came into force 1982), The International Convention on Safe Containers (adopted 1972, came into force 1977), and the convention on International Regulations for Preventing Collisions at Sea (COLREGS) (adopted 1972, came into force 1977). The 1972 COLREGS convention contained, among other provisions, a section devoted to Traffic Separation Schemes, which became binding on member states after having been adopted as recommendations in prior years. One of the most important conventions is the International Convention for the Prevention of Pollution from Ships (MARPOL 73\/78), which was first adopted in 1973, amended by Protocol in 1978, and became binding in 1983. This convention built on a series of prior conventions and agreements dating from 1954, highlighted by several severe pollution disasters involving oil tankers. <img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"832\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/sample-page\/image251#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image251.jpg\" data-orig-size=\"1024,1280\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;6555b&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Image251\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image251-240x300.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image251-819x1024.jpg\" class=\"size-medium wp-image-832 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image251-240x300.jpg\" alt=\"Image251\" width=\"240\" height=\"300\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image251-240x300.jpg 240w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image251-819x1024.jpg 819w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image251.jpg 1024w\" sizes=\"auto, (max-width: 240px) 100vw, 240px\" \/>The MARPOL convention reduces the amount of oil discharged into the sea by ships, and bans discharges completely in certain areas. A related convention known as the London Dumping Convention regulates dumping of hazardous chemicals and other debris into the sea. The IMO also develops minimum performance standards for a wide range of equipment relevant to safety at sea. Among such standards is one for the Electronic Chart Display and Information System (ECDIS), the digital display deemed the operational and legal equivalent of the conventional paper chart. Texts of the various conventions and recommendations, as well as a catalog and publications on other subjects, are available from the Publications Section of the IMO at 4 Albert Embankment, London SE1 7SR, United Kingdom. 125. The International Association of Marine Aids to Navigation and Lighthouse Authorities The International Association of Marine Aids to Navigation and Lighthouse Authorities (formerly IALA) brings together representatives of the aids to navigation services of more than 80 member countries for technical coordination, information sharing, and coordination of improvements to visual aids to navigation throughout the world. It was established in 1957 to provide a permanent organization to support the goals of the Technical Lighthouse Conferences, which had been convening since 1929. The General Assembly of IALA meets about every 4 years. The Council of 20 members meets twice a year to oversee the ongoing programs. Five technical committees maintain the permanent programs:<\/p>\n<ul>\n<li>The Marine Marking Committee<\/li>\n<li>The Radionavigation Systems Committee<\/li>\n<li>The Vessel Traffic Services (VTS) Committee<\/li>\n<li>The Reliability Committee<\/li>\n<li>The Documentation Committee<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"831\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/sample-page\/image248#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image248.jpg\" data-orig-size=\"1280,1024\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;6555b&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"Image248\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image248-300x240.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image248-1024x819.jpg\" class=\"size-medium wp-image-831 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image248-300x240.jpg\" alt=\"Image248\" width=\"300\" height=\"240\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image248-300x240.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image248-1024x819.jpg 1024w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/02\/Image248.jpg 1280w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>IALA committees provide important documentation to the IHO and other international organizations, while the IALA Secretariat acts as a clearing house for the exchange of technical information, and organizes seminars and technical support for developing countries. Its principle work since 1973 has been the implementation of the IALA Maritime Buoyage System, described in Chapter 5, Visual Aids to Navigation. This system replaced some 30 dissimilar buoyage systems in use throughout the world with 2 major systems. IALA is based near Paris, France in Saint-Germaineen- Laye. 126. The Radio Technical Commission for Maritime Services The Radio Technical Commission for Maritime Services is a non-profit organization which serves as a focal point for the exchange of information and the development of recommendations and standards related to all aspects of maritime radiocommunications and radionavigation. Specifically, RTCM: \u2022 Promotes ideas and exchanges information on maritime radiocommunications and radionavigation. \u2022 Facilitates the development and exchange of views among and between government and nongovernment interests both nationally and internationally. \u2022 Conducts studies and prepares reports on maritime radiocommunications and radionavigation issues to improve efficiency and capabilities. Both government and non-government organizations are members, coming from the U.S. and many other nations. <img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1480\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1493\/100_1764#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1764.jpg\" data-orig-size=\"2592,4608\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;3.9&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1406984575&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.1&quot;,&quot;iso&quot;:&quot;64&quot;,&quot;shutter_speed&quot;:&quot;0.0125&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_1764\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1764-168x300.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1764-576x1024.jpg\" class=\"size-medium wp-image-1480 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1764-168x300.jpg\" alt=\"100_1764\" width=\"168\" height=\"300\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1764-168x300.jpg 168w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1764-576x1024.jpg 576w\" sizes=\"auto, (max-width: 168px) 100vw, 168px\" \/>The RTCM organization consists of a Board of Directors, and the Assembly consisting of all members, officers, staff, technical advisors, and working committees. Working committees are formed as needed to develop official RTCM recommendations regarding technical standards and regulatory policies in the maritime field. Currently committees address such issues as maritime safety information, electronic charts, emergency position-indicating radiobeacons (EPIRB\u2019s), personal locator beacons, ship radars, differential GPS, GLONASS, and maritime survivor locator devices. The RTCM headquarters office is in Alexandria, VA. 127. The National Marine Electronic Association The National Marine Electronic Association (NMEA) is a professional trade association founded in 1957 whose purpose is to coordinate the efforts of marine electronics manufacturers, technicians, government agencies, ship and boat builders, and other interested groups. In addition to certifying marine electronics technicians and professionally recognizing outstanding achievements by corporate and individual members, the NMEA sets standards for the exchange of digital data by all manufacturers of marine electronic equipment. This allows the configuration of integrated navigation system using equipment from different manufacturers. NMEA works closely with RTCM and other private organizations and with government agencies to monitor the status of laws and regulations affecting the marine electronics industry. It also sponsors conferences and seminars, and publishes a number of guides and periodicals for members and the general public.<\/p>\n<h3>128. International Electrotechnical Commission<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1482\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1493\/100_1766#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1766.jpg\" data-orig-size=\"4608,2592\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;10.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1406984668&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.1&quot;,&quot;iso&quot;:&quot;64&quot;,&quot;shutter_speed&quot;:&quot;0.0125&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_1766\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1766-300x168.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1766-1024x576.jpg\" class=\"size-medium wp-image-1482 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1766-300x168.jpg\" alt=\"100_1766\" width=\"300\" height=\"168\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1766-300x168.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1766-1024x576.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>The International Electrotechnical Commission (IEC) was founded in 1906 as an outgrowth of the International Electrical Congress held at St. Louis, Missouri in 1904. Some 60 countries are active members. Its mission is to develop and promote standardization among all nations in the technical specifications of electrical and electronic equipment. These technologies include electronics, magnetics, electromagnetics, electroacoustics, multimedia, telecommunications, electrical energy production and distribution, and associated fields such as terminology and symbology, compatibility, performance standards, safety, and environmental factors. <img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1481\" data-permalink=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/archives\/1493\/100_1761#main\" data-orig-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1761.jpg\" data-orig-size=\"4608,2592\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;10.8&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;KODAK EASYSHARE Touch Camera, M5370&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;1406984526&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;5.1&quot;,&quot;iso&quot;:&quot;64&quot;,&quot;shutter_speed&quot;:&quot;0.008&quot;,&quot;title&quot;:&quot;&quot;}\" data-image-title=\"100_1761\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1761-300x168.jpg\" data-large-file=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1761-1024x576.jpg\" class=\"size-medium wp-image-1481 alignright\" src=\"http:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1761-300x168.jpg\" alt=\"100_1761\" width=\"300\" height=\"168\" srcset=\"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1761-300x168.jpg 300w, https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/08\/100_1761-1024x576.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/>By standardizing in these areas, the IEC seeks to promote more efficient markets, improve the quality of products and standards of performance, promote interoperability, increase production efficiency, and contribute to human health and safety and environmental protection. Standards are published by the IEC in the form of official IEC documents after debate and input from the national committees.<br \/>\nStandards thus represent a consensus of the views of many different interests. Adoption of a standard by any country is entirely voluntary. However, failure to adopt a standard may result in a technical barrier to trade, as goods manufactured to a proprietary standard in one country may be incompatible with the systems of others. IEC standards are vital to the success of ECDIS and other integrated navigation systems because they help to ensure that systems from various manufacturers in different countries will be compatible and meet required specifications.<\/p>\n <\/div>\r\n\t\t","protected":false},"excerpt":{"rendered":"<p>100. The Art And Science Of Navigation Marine navigation blends both science and art. A good navigator constantly thinks strategically, operationally, and\u00a0tactically. He plans each voyage carefully. As it proceeds,\u00a0he gathers navigational information from a variety of\u00a0sources, evaluates this information, and determines his\u00a0ship\u2019s position. He then compares that position with his\u00a0voyage plan, his operational commitments,&hellip;<\/p>\n","protected":false},"author":1,"featured_media":1208,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"Cruising Log of the Murrelet | MARINE NAVIGATION http:\/\/wp.me\/p4nQeu-rl","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[5],"tags":[27,18,40],"class_list":["post-1695","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-exex2014","tag-boating","tag-cruising","tag-water-ballast"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-content\/uploads\/2014\/06\/2991.jpg","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p4nQeu-rl","_links":{"self":[{"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/posts\/1695","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/comments?post=1695"}],"version-history":[{"count":63,"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/posts\/1695\/revisions"}],"predecessor-version":[{"id":1939,"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/posts\/1695\/revisions\/1939"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/media\/1208"}],"wp:attachment":[{"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/media?parent=1695"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/categories?post=1695"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.eskimo.com\/~mighetto\/murrelet\/Wordpress\/wp-json\/wp\/v2\/tags?post=1695"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}