There are several boat designs that can be expected as the move away from fossil fuels continues. These include:
- Solar-powered boats: Solar power is a renewable energy source that can be used to power boats. Jeroen Droogsma, head of design studies at Vripack, has been working with solar-powered boats for 10 years see 1.
- Hydrogen fuel cell technology: The Netherlands and Norway are leaning towards hydrogen fuel cell technology for marine application1. Hydrogen can be supplied as a pure gas held in tanks or manufactured on site through the electrolysis of water see 1.
- Methanol and other fossil-fuel alternatives: Some pilot projects are using fossil-fuel-based methanol to power ships, and some companies have signed deals to secure enough green methanol to start using it as a fuel see 2.
- Wind-assisted propulsion: Wind assisted propulsion is the practice of using sails or a type of wind capture device see 3.
- Fuel cell propulsion: Fuel cells convert fuel more efficiently than traditional combustion engines, reducing pollution and greenhouse gas emissions see 3.
- Non-fossil paraffinic fuels and alcoholic fuels: Feadship has developed a fully integrated system that is able to store both non-fossil paraffinic fuels and alcoholic fuels at full capacity see 4.
- Hull form optimization: Hull form optimization is a technique used to reduce drag and improve fuel efficiency see 5.
In summary, boat designs that can be expected given the move away from fossil fuels include solar-powered boats, hydrogen fuel cell technology, methanol and other fossil-fuel alternatives, wind-assisted propulsion, fuel cell propulsion, non-fossil paraffinic fuels and alcoholic fuels, and hull form optimization.
There are also attractive retrofitting possibilities.
Electronic engine and transmission controls (EEC) can improve the fuel economy of a dual screw boat by optimizing the engine and transmission performance. As with most boats, the fuel efficiency depends on several factors such as the boat’s size, weight, and engine specifications. According to1, electronic controls can increase propulsion’s efficiency by 3-8% for single-screw vessels
Driving a given yacht at a given speed under the same load and sea conditions depends on the amount of thrust delivered by the propeller or propellers. Hence, different propellers will be mounted for fuel efficiency than when the operator wants maximum speed.
When family members decided to complete America’s Great Loop, they selected a single screw Mainship trawler after consulting with loop experts knowledgeable of the most fuel-efficient propulsion system for a boat running at displacement speeds. A single-engine trawler is more economical than a twin-screw, semi-displacement boat according to.. https://www.passagemaker.com/technical/feel-the-burn. However, this depends on the boat’s hull shape, weight distribution and cruising area conditions.
While historically, single-engine installations in yachts have been thought to be more economical than twin-engine setups, this is mostly a myth. The number of engines and screws have little to do with overall expenditures. The speed, load, sea conditions and amount of thrust delivered by the propeller or propellers is what is important. In general, twin screw configurations are used for maneuverability and redundancy rather than fuel efficiency2. However, 2 also suggests that twin screw configurations can be more fuel-efficient than single screw configurations, with an estimated 15% difference in overall fuel efficiency. Fuel consumption is measured in gallons per hour, and it can be estimated using the formula GPH = (specific fuel consumption x HP)/Fuel Specific Weight. The specific fuel consumption and fuel specific weight depend on the type of fuel used. Gasoline weighs about 6.1 pounds per gallon, while diesel fuel weighs about 7.2 pounds per gallon. GPH is used rather than MPG because currents and wind impact the numbers of miles traveled but not hours.
To optimize fuel efficiency during a long-distance boat trip, there are several tips that can be followed. According to1, one of the major factors that affects the overall performance of a boat-engine combination and its fuel consumption is the propeller. Matching the correct propeller to the boat and cruising area can improve fuel economy. Additionally, it is important to distribute weight evenly along the boat’s centerline and consider the boat’s fore-and-aft balance. This includes positioning passengers, gear, and fuel evenly and adjusting the boat’s trim using trim tabs or the motor’s tilt and trim function when necessary2.Furthermore, 3 suggests that installing a fuel flow meter can help monitor fuel efficiency in real-time. It is also important to ensure that the engine is well-maintained and that the oil level is neither too little nor too much, as this can harm the engine, affect overall performance, and reduce fuel efficiency.Finally, 4 recommends incrementally adding up tactics that improve fuel economy, such as reducing speed, avoiding idling, and planning the route to take advantage of favorable currents and winds. It is also important to calculate the boat’s fuel consumption rate using the appropriate formula5 and to develop a boat fuel consumption chart to monitor fuel usage during the trip.
My family and I spent a decade with twin screw 60 foot and larger wooden and steel motor vessels. This was before bow and stern thrusters. Owing to always increasing fuel costs, we transitioned to smaller displacement hulled sailboats and the Macgregor 26x power sailor. But the desirability of bow and stern thrusters was never clear to me until 2023.
With both bow and stern thrusters, the maneuverability of a dual screw vessel can be obtained. We learned that putting one engine in reverse and the second in forward was not necessary to make tight turns for docking MV Seahome. We could use thrusters instead. Best of all, with both thrusters, Seahome could parallel park in between boats already tied to the fuel dock. What’s more, there was no awkward dismounting the boat to tie off lines or need to request assistance from shore to take lines. We didn’t need a boat hook to pick up lines made ready for us. The two thrusters could be put in hold mode, thereby holding the boat against the dock until we stepped off the swim platform to affix our deck lines.
Hence, while twin screw configurations are generally believed best for maneuverability, that advantage over single screw design is lost when bow and stern thrusters are available. As discussed above, the fuel efficiency of a single screw can be met (contrary to general perceptions) with twin screws. Nonetheless, the common perception is that a single screw is a better design. Now let’s consider redundancy.
With the renovation of Western Flyer, we had a number of choices of what to use for a propulsion system. We really wanted to do a pure electric vessel, but then reality intruded. This is a rapidly changing technology, but prices are still very high. We estimated that it would cost at least $1.2M to install the necessary batteries and motors, and whatever we came up with would likely be obsolete within 5 or 6 years. That’s a cost that we just couldn’t afford.
It would also come with a number of operational limitations. While it would be very green in a state such as California with its relatively low-carbon electrical grid, that would not be the case in Mexico, where we expect to spend up to a quarter of our time. There, the grid is largely coal and oil-fired, leading to total emissions that would actually be higher than a modern tier-four diesel!
So, we chose to do the next best thing: a diesel-electric hybrid. This is a system that is largely diesel-powered but can switch to electric mode for relatively brief periods of time. Besides being cleaner, a diesel-electric has several other advantages. The Western Flyer will have to hold research stations for long periods of time, which requires a slow-turning motor that reverses a lot, both of which diesels hate doing. For a long-haul, cargo-carrying ship that’s not a problem — they just put the thing in gear in Yokohama and don’t take it back out until they reach Oakland — but, for us, who might be reversing hundreds of times in a day, it would be inefficient and mechanically troublesome. With a hybrid system, we can just switch to electric mode, allowing speeds from zero to full max 1850 RPM, in forward and reverse, with just a single control and no clutch engaging and disengaging.
Running a hybrid also opens up some very interesting research possibilities. When in electric mode, the boat, with its wooden hull and electric motor, will be extraordinarily quiet and less intrusive in near-shore environments. We wonder what scientists might be missing when approaching an area with a thumping diesel and a loud exhaust stack. We will be able to sit quietly in a patch of water for long periods of time, watching and observing.
The system we chose uses a traditional John Deere 6135 marine diesel (425 HP or 320 kW), mated to a Transfluid HM3350, manufactured in Italy. Looking a bit like the Starship Enterprise, the unit sits between the diesel and the gearbox. It has two 50 kW motors (the “warp drives”), which are engaged through a pinion gear and clutching mechanism when in electric mode.https://www.westernflyer.org/
It should be apparent from the above quote that the single-engine single-screw MV Western Flyer has engine redundancy like a twin-engine twin-screwed vessel. It gains that advantage by the electric motor from Italy.
I view the Wester Flyer as Yacht Design’s Future. It is not just its retrofit to a hybrid but also the boat’s construction in carbon neutral wood. The days of new plastic boat hulls are pretty much over for the next 30 years because of the cost of fossil extractions, there link to global warming and the backlash that can be expected from knowledgeable young boat buying consumers.
Architects note that the most green structure is the one already built and that applies to boats as well as land structures. So conservation of plastic hulls – especially the efficient ones – and upgrades in propulsion will be the most common design activity. New hull construction should be from something other than fossil extractions. Wood, Aluminum and Steel are alternatives – not fiberglass – unless it is made from carbon neutral not-fossil ingredients. As explained below, those carbon neutral ingredients are needed for refining renewable fuel.
Drivers in Europe fill up their diesel cars with palm oil biodiesel. In 2018, 65% of all the palm oil imported into the EU was used for energy. More than half (53%) of all EU palm imports were used to make biodiesel for cars and trucks and 12% was used to generate electricity and heating. Palm oil used for biodiesel grew again in 2018 – by 3% – while the use of palm oil to make food and animal feed dropped significantly, by 11%.
In the USA, laws protecting fossil extractions and non palm oil biofuel do not exist and refineries are synthesizing palm oil into chemically identical to fossil diesel fuel. The United States has a mandatory biofuel program that requires the use of renewable fuels, including palm oil, in transportation. In tropical areas, forest oil palm farms are replacing foodstock crops used for biofuel like soy and sugar cain. It takes one quarter of the land to produce the same amount of fuel. The trees produce 18 months after planting and can be managed into rainforests and wilded. The cure for global warming is palm oil production because trees absorb CO2 and fossil extractions can be halted in years rather than decades. It is currently less expensive than fossil based extractions. And the future for boat designs involves using refined palm oil to replace fossil fuels while going electric as well as using wind. In the near term, it is renewable palm oil based fuels driving yacht designs because current engines do not need replacement or modification and fuel consumption can be lessened with electronics and changes in operation.
Concern for the environment impacts boat design beyond just propulsion. For decades there has been concern regarding waste disposal.
- Boaters are not allowed to discharge sewage, treated or untreated, into Puget Sound1235. Puget Sound is about 95 miles long and 1 to 5 miles wide, with its northern boundary at Admiralty Inlet and ending in the south at the city of Olympia4.
- Puget Sound is now a no-discharge zone for vessel sewage3.
- The vessel sewage rule is effective as of May 10, 2018, for all recreational boats, and was adopted on April 9, 20183.
- Most recreational boats already have holding tanks that can store sewage until it can be safely disposed of at an onshore or mobile pumpout facility, or discharged in the open ocean beyond three miles from shore4.
- Federal law allows vessels to dump raw sewage only in waters more than three miles from shore5.
- Discharge of untreated sewage is only permitted beyond the three nautical mile ocean limit6.
In summary, recreational boaters in Washington State are not allowed to discharge sewage, treated or untreated, into Puget Sound, which is now a no-discharge zone for vessel sewage. Most recreational boats already have holding tanks that can store sewage until it can be safely disposed of at an onshore or mobile pumpout facility, or discharged in the open ocean beyond three miles from shore. Federal law allows vessels to dump raw sewage only in waters more than three miles from shore, and discharge of untreated sewage is only permitted beyond the three nautical mile ocean limit.
The above regulations are routinely ignored by all but the most environmentally conscious USA boaters and charter operators. Puget Sound is an inlet of the Pacific Ocean, located along the northwestern coast of the US state of Washington25.
Some believe it is OK to dump treated sewage into The Strait of Juan de Fuca which flushes water from Puget Sound into the Pacific Ocean twice per day. See below:
- The Strait of Juan de Fuca supports significant populations of groundfish, clams, shrimp, sea urchins, and Dungeness crab, as well as other fisheries resources5.
- The cleanest water Victoria has ever put into the ocean is being discharged into the Strait of Juan de Fuca6.
- The Strait of Juan de Fuca has been polluted by untreated sewage from Victoria, British Columbia, for over a century36.
- Sewage dumped into the Juan de Fuca Strait from places like the Capital Regional District accounted for billions of liters of untreated sewage13.
- Decades of dumping raw sewage have killed Victoria’s ocean floor1.
- The marine environment and biota of the Strait of Juan de Fuca, Strait of Georgia, and Puget Sound have been impacted by pollution3.
- The Strait of Juan de Fuca sees over 8,000 transits of deep-draft container ships, cargo4.
In summary, the marine environment in the Strait of Juan de Fuca is impacted by pollution, but it also supports significant populations of fisheries resources. The recent sewage treatment plant in Victoria, British Columbia (2020) has ended the practice of releasing untreated sewage directly into the ocean near Victoria, which is a positive development for the marine environment in the Strait of Juan de Fuca. Boaters are unaware that Victoria no longer dumps raw sewage into the Strait.
The rules for Canadian Boaters are the same in Puget Sound as for USA boaters.
- Lax regulations allow the discharge of raw sewage across much of the BC coast1.
- Currently, Canadian regulations only prohibit the dumping of sewage within three miles of the shoreline2.
- A person must not discharge domestic sewage or waste from a trailer, camper, transportable housing unit, boat, or houseboat onto land, into any reservoir, or…3.
- Transport Canada regulations prohibit the discharge of raw sewage directly into the water4.
- Boaters are not allowed to discharge sewage, treated or untreated, into Puget Sound56.
- The vessel sewage rule is effective as of May 10, 2018, for all recreational boats, and was adopted on April 9, 20186.
- Most Canadian recreational boats already have holding tanks that can store sewage until it can be safely disposed of at an onshore or mobile pumpout facility, or discharged in the open ocean beyond three miles from shore6.
- Graywater discharges are not affected by the vessel sewage rule6.
- Even small amounts of sewage discharges over or near shellfish beds can cause enough pollution to require harvest closures6.
In summary, the regulations for sewage discharge from recreational boaters in British Columbia are relatively lax, and Canadian regulations only prohibit the dumping of sewage within three miles of the shoreline. However, Transport Canada regulations prohibit the discharge of raw sewage directly into the water. Boaters are not allowed to discharge sewage, treated or untreated, into Puget Sound, which is now a no-discharge zone for vessel sewage. Most recreational boats already have holding tanks that can store sewage until it can be safely disposed of at an onshore or mobile pumpout facility, or discharged in the open ocean beyond three miles from shore. Graywater discharges are not affected by the vessel sewage rule, but even small amounts of sewage discharges over or near shellfish beds can cause enough pollution to require harvest closures.
Owing to the above, the yacht design future will will involve addressing waste in a more significant way. The designs for boats that are chartered will be the first.
- All boats and vessels are required to store their sewage until it can be safely disposed of at an onshore or mobile pumpout facility, or hold it until it can be discharged in the open ocean beyond three miles from shore4.
- Previously, federal regulations allowed treated sewage to be discharged anywhere in Puget Sound, and untreated sewage could be discharged as long as the boat was more than three miles from shore. With the no-discharge zone now in effect, no boat of any kind or size can discharge sewage wastewater anywhere within the zone4.
- Boat owners or rig operators face stern boat sewage regulations and steep repercussions surrounding the use of their marine sanitation device6.
- To help keep shared water safe, it’s against federal law to discharge any sewage that you haven’t safely treated. This applies to any vessel that’s in U.S. navigable waters6.
- Boat charter operators are required to follow all of the main boat sewage regulations from previous years6.
Besides going 3 miles into the Pacific Ocean, which is unusual for a recreational boater, there are three methods of emptying a boat’s holding tank in my cruising area, the Salish Sea. Traveling at least three miles offshore in Canada and emptying there is still legal. You can pump out the tank at a dock providing that service or call for a pump out service boat, or you can let the legally liable charter service do the pumping. The latter option makes vessels with large holding tanks desirable. Boats will be designed and modified with that in mind.
In summary, USA boat charter operators are required to store sewage until it can be safely disposed of at an onshore or mobile pumpout facility, or hold it until it can be discharged in the open ocean beyond three miles from shore. Federal law prohibits the discharge of any sewage that has not been safely treated, and boat charter operators are required to follow all of the main boat sewage regulations from previous years.
Recreational boaters may ignore requirements to use pump out stations because of the nature of the task. However, there are several ways that boaters are encouraged to use pump out stations.
- Information and education programs that encourage boaters to use pump outs1.
- Easy access to marina pump out stations24.
- Guidelines that encourage everyone to use the shoreside facilities before casting off3.
- Portable pump-out stations like the Todd Waste Caddy that can be brought to the boat4.
- Grant programs that help fund the construction, renovation, and maintenance of pump out and dump stations to service pleasure boats5.
These initiatives aim to make the pump out process more convenient and accessible for boaters, and to raise awareness about the importance of using pump out stations to keep the water clean.
- Remove the cap from the boat’s deck waste fitting.
- Insert the pumpout hose nozzle into the deck fitting.
- Turn on the pump. If there is a hose valve, open it to start the suction.
- When no waste is seen in the sight glass, close the hose valve and remove the nozzle from the deck fitting.
- Put the nozzle (with the open valve) in a bucket of water for 15 seconds to rinse the hose. If desired, rinse the boat’s holding tank with water and pump it dry.
- Close the valve, put away the hose, and replace the deck fitting cap.
There are also ship board pumps that can be involved in emptying a boat’s holding tank, these are macerating and bellows pumps.
A macerating pump is a type of pump that grinds up solid waste and toilet paper into small pieces, making it easier to pump out of the holding tank. It is commonly used in marine applications to pump out holding tanks. Here are some relevant information about macerating pumps123:
- Macerator pumps are the key to a number of important chores on a boat.
- They are used to pump out holding tanks and can be used in non-gravity feed situations.
- They can be self-priming and have run-dry protection.
- They are available in different sizes and capacities.
- They can be mounted on the boat or portable.
Therefore, a macerating pump can be used at a marine pump out station to pump out holding tanks.
- Macerating pumps grind up solid waste and toilet paper into small pieces, making it easier to pump out of the holding tank.
- They can be used in non-gravity feed situations, which means they can pump waste uphill or over a long distance.
- They can be self-priming and have run-dry protection, which means they can be turned on and off easily and won’t get damaged if they run without liquid going through them.
- They can be used to empty fish boxes as well as holding tanks.
- They can prevent clogs and blockages in the pump out station’s hoses and pipes.
Overall, using a macerating pump can make the pump out process more efficient and effective, especially in situations where gravity feed is not possible.
- The macerator pump should not be run without liquid going through it, as running dry can damage the impeller and the pump itself.
- The macerator control should be designed to “jog” the impeller once a week when power is on to prevent the impeller from taking shape and to help prevent it from running dry1.
- The macerator pump should be primed before use2.
- The macerator pump should be checked for clogs and blockages regularly3.
- The macerator pump should not handle hard objects, rags, or feminine napkins4.
It is also important to follow the manufacturer’s instructions for maintenance and operation of the macerating pump.
Bellows pumps are sometimes used instead of macerator pumps for marine applications. Here are some relevant information about bellows pumps1:
- Bellows pumps are non-macerating waste discharge pumps that use a flexible rubber bellows to pump out waste.
- They are simpler and less expensive than macerator pumps.
- They are less prone to clogging than macerator pumps.
- They are not as efficient as macerator pumps in breaking up solid waste and toilet paper, which can lead to blockages in the pump out station’s hoses and pipes.
Whether a bellows pump is better than a macerator pump depends on the specific needs and preferences of the boat owner. Bellows pumps require less maintenance than macerator pumps, but they are not as effective in breaking up solid waste. Ultimately, the choice between the two types of pumps depends on the boat owner’s priorities and budget.
No place on a vessel will be changed as much in the near future as the placement of instruments. We used four Garmen Chart Plotters on Sea Home. The most up to date was on the main deck. Another was on the fly bridge. A third was at the center console of the dinghy. And the fourth remained on our Macgregor 26x but we brought along the iPad companion to it. That iPad contained Active Captain Software from Garmen with the most up to date charts. We also used cell phones for tide and currents, AIS tracking, anchor alarm, and weather reports. The above has the potential to replace all of that plus Sea Home’s entertainment system.