As hybrid and electric cars such as Tesla and the Toyota Prius have grown in popularity and become more practical options for mainstream consumers, boat manufacturers have begun to follow suit by designing and building electric boats. Experienced boaters tend to have an appreciation for the natural aquatic environment and ecosystem around them. From following the tides to coexisting with wildlife, being eco-conscious is deeply ingrained in the boating lifestyle. New technologically advanced boat models are now making hybrid gas/electric and electric propulsion not only feasible but also enjoyable. In this guide we’ll take a look at some of the boat brands, models, engines, manufacturers, and propulsion systems that are beginning to heat up the solar, electric/gas and alternative energy market in 2022 – bringing sustainability to the forefront of the marine industry. Topics include:
- How does a hybrid electric boat work?
- What are the benefits associated with hybrid and electric boats?
- Hybrid and electric boats and the current marine market.
- What are the problems with marine hybrid and electric boating?
- The technology behind electric and hybrid boating
- Serial and parallel hybrid boats
- Fully electric marine propulsion systems
- Electric and hybrid marine engine manufacturers
- Cutting-edge concept designs in solar boating
- Examples of electric and hybrid boats
- Fuel efficiency in hybrid boat engines
- Hybrid solutions for sailboats
- The future of hybrid and electric boating
How does a Hybrid Electric Boat Work?
A hybrid marine propulsion system is any combination of a combustion engine and an electric motor. Electricity can be produced by one or a combination of the following: a combustion engine generator, a wind generator, a towed water generator or solar panels. A purely electric solution with solar panels is enviable due to its zero carbon footprint and low operating costs and various takes on theses systems have been gaining traction on alternative energy vessels. Advances in both energy storage and solar panel technology have reduced costs and physical footprint making solar power propulsion systems more feasible for use on boats.
What are the Benefits Associated with Hybrid and Electric Boats?
There are numerous benefits to electric motor propulsion including that it’s quieter, more efficient at lower speeds and less smelly. It’s also expected to lower overall costs of ownership by reducing or eliminating the needs for oil and transmission fluid changes, filter and impeller replacements and starter problems. There’s less to winterize too. Additionally, unlike diesel or gas engines, electric motors provide full torque instantly so boats get up on plane faster. Aftermarket conversions (which currently make up the lion’s share of the market) can use existing drive shafts and components so there is a cost-savings when re-powering.
Hybrid and Electric Boats and the Current Marine Market
As mentioned, now that hybrid and pure electric propulsion systems have proliferated within the automotive industry, hybrid or electric boats are beginning to gain steam. Still, the marine world is a relatively small niche market that tends to follow rather than lead other industries in terms of innovation. Currently only less than two-percent of boats today are integrating electric or hybrid propulsion. This slow adaption is partly due to the unique issues of boating. Boats have a different frequency and variance of use than cars and the market has many segments (ferries, sailboats, small high speed planers, large distance cruising yachts, etc.) where boats are used differently, making it hard to build one solution to fit all applications. However, a few companies are trying to change all that.
Power and auxiliary sailboats are typically propelled by inboard or outboard engines using diesel or gasoline fuel. A growing appeal has been placed on electric motors for these purposes – i.e. pure electric engines powered by large battery banks.
As with any new technology, there’s an adoption curve. The early adopters are the technologists, visionaries and tinkerers and they make up only about 15% of the market. In marine, these are distance sailors that need efficient sustainability and autonomy but they’re also ferries and water taxis that operate on bodies of water where combustion engines aren’t allowed. Then come the trailerable towboats, tenders and fishing boats as well as charter boats to fill the boating sweet spot of the 25 to 75 foot midrange power market.
What are the Problems with Marine Hybrid and Electric Boating?
Because e-propulsion is in its infancy in the marine market, available solutions are few and they’re expensive. So far, most electric boats have also been slow and small and had very restricted range, but that is changing as battery capacities continue to evolve. There’s also the problem of infrastructure, which is the same for automotive: What is the range of these new vessels and where do they recharge? It varies quite a bit by boat and by operational parameters, but just like a Tesla that you’d probably want to know where and when you can charge up before beginning any lengthily voyage.
The Technology Behind Electric and Hybrid Boating
Use of brushless permanent magnet electric motors and advances in lithium-ion battery technology have allowed for leaps to be made in the rush to marine electric. Lithium-ion batteries are half as heavy as lead-acid batteries and last three times as long, and advances in their effectiveness and stability have been significant.
German electric motor manufacturer Torqeedo teamed with BMW and “marinized” the automaker’s i3 and i8 Series batteries for use in a variety of boats. They added a rugged damping frame to minimize shock, a venting system to channel gasses safely and waterproofing to IP67 standard. The new batteries tout a 31% increase in capacity (energy density) over the previous similarly sized model and their footprint (roughly 5’ x 3’ x 6”) can be fitted into even the most compact engine spaces.
Serial and Parallel Hybrid Boats
Currently, two approaches are battling it out on the water – serial and parallel hybrids. The serial hybrid system integrates a range-extending generator. The engine drives the generator, which powers an electric motor connected to the driveshaft—there is no mechanical connection between the engine and the driveshaft. A parallel system has a direct mechanical connection between the engine and the driveshaft but also drives an additional electric motor that operates as a generator – on the same shaft.
Range-extending power regeneration may be accomplished by a free-spinning propeller, which is easy to do on a moving sailboat and can be accomplished by using only one engine at a time on a powerboat. UK motor manufacturer Hybrid Marine is offering a third option: a multimode system that combines the best of serial and parallel approaches with an arrangement of clutches and gears.
Fully Electric Marine Propulsion Systems
Outboard power systems are the easiest to replicate and replace with electric motors, and so many of the first available fully electric systems were electric outboards. Today there are a number of electric outboards on the market in ranging sizes, however, many of the companies producing additional models have come and gone. Currently, Evoy has a 120-hp motor on the market and claims that by 2024, 200-, 300-, and 400-hp models will be available. See our Ultimate Guide to Outboard Motors to learn about some of the offerings currently on the market today.
Torqeedo’s Deep Blue 100i motor is the first fully integrated inboard electric propulsion system, which is available in two versions – 2400 rpm for faster planing boats and 900 rpm for heavier displacement vessels up to 120 feet. The focus of the entire system, from helm to prop, is on safety and it’s expanded the target market in terms of size, speed and typical use of the vessel. A comprehensive propulsion system is a complex combination of voltages and that makes things complicated on the water. For example, one inboard motor installation may include all of the following:
- 400 VDC for propulsion using automotive battery technology
- 110/240 VAC for hotel loads on AC
- 24 VDC for onboard electrics
- 12 VDC to “wake up” the larger batteries and generator/range extender
- Bi-directional switching between 24 and 400V networks
That’s a lot of technology to pack into space-sensitive hulls. It also adds complexity and cost.
Electric and Hybrid Marine Engine Manufacturers
Manufacturers who have focused on this market include Torqeedo, based in Germany, that subsidizes electric motor research. Another contender is Elco from Athens, New York, which, like Torqueedo, offers both inboard and outboard electric motors. Also, we mustn’t forget the classic Minn Kota trolling motors that have kept anglers emission-free for decades.
Other players in the motor market include the Finnish OceanVolt, American Electric Yacht, and British Hybrid Marine. California-based Electroprop sells pre-packaged 6 and 21 kW systems that boat builders can drop into their existing engine rooms. Swedish diesel engine giant, Volvo Penta, in 2019 announced the intention to introduce electric motors installed inline between their diesels and IPS pods, and is working with French catamaran builder, Fountaine Pajot, on a Lucia 40 sailing cat with hybrid power.
There are many players all searching for the killer app in marine alternative energy propulsion. It’s likely a few will survive while others are purchased or disappear in an increasingly competitive market.
Cutting-edge Concept Designs in Solar Boating
Fully-electric boats are making great progress but they’re still a small portion of the boating market. However, highly promoted concept designs are helping raise awareness of alternative energy solutions and one such advocate is Touranor SolarPlanet, a 102-foot catamaran with wave-piercing hulls. The futuristic Swiss SolarPlanet cost 15 million Euros when it was launched in 2010 and circumnavigated the globe in 585 days strictly on electric power generated by the 500 solar panels on her top deck. Although the design’s top speed was 14 knots, the average speed around the globe was 5 knots.
After that impressive feat, the boat was donated for research. Boats like this may be one-offs but they’re helping shine the spotlight on what can be accomplished in alternative energy propulsion and the direction that boating is taking.
Examples of Electric and Hybrid Boats
Due to advances in both motor design and battery technology, electric propulsion is reaching diverse segments of the boating market from small planing boats to large cruising yachts both power and sail. Some well-known boat builders have already dipped their toes into these alternative power waters.
Candela produces the C-7 and C-8 models, which are entirely unique among electric boats in that they’re foiling craft. Riding on a forward foil and an aft foil on the motor pod, the Candelas can hit speeds up to 30 knots and claims a reduction in energy consumption of up to 80%. As a result, range can be extended out to 50-plus nautical miles while cruising at 24 knots. Additionally, the foils are retractable for slow speed and shallow water use.
Duffy Boats has been building a line of electric leisure cruisers for the past 50 years and is one of the oldest manufacturers dedicated to electric power around. You’ll see many of these in rental service in tourist areas on cocktail cruises. See Duffy electric boats for sale on BoatTrader.
Frascher Mirage 740
The Austrian Frauscher Mirage 740 Air was previously available with a Mercury 350-hp with stern drive but today can come with Torqeedo’s Deep Blue system that combines a high-rpm 100 kW brushless inboard motor with twin BMW i3 Series 40 kW batteries. The high-capacity lithium batteries are stacked one above the other in the engine compartment aft. The Frauscher is ideal for areas where recharging (with ordinary shore power) is available and its system can charge up to 75 percent capacity in less than 1.5 hours. Top speed is 24 mph at 2200 rpm. The range is approximately 20 miles. (Currently, the electric power package adds $120,000 to the Frauscher’s base price.)
Hinckley Dasher Electric Boat
Sleek and stylish, the Hinckley Dasher is a fully electric luxury yacht. Designed by Michael Peters, the 28-foot Hinckely Dasher was built from the ground up for electric propulsion. The resin-infused build mixes epoxy and carbon fiber with a synthetic core so the design weighs only 6,500 pounds. And weight is critical in electric mobility.
The Dasher is propelled by twin 40 kWh BMW i3 lithium ion batteries driving twin 80 hp straight shaft inboard motors. These are the same batteries used in the BMW i3 automobile and should last 9 years or 9,000 cycles. Expect to reach 23 knots of top speed or cruise at 8.5 knots. The maximum range at 20 knots will be 40 miles. Four hours is all that’s needed to charge from zero to full capacity, which is a little faster than a Tesla.
Greenline Hybrid Yachts
Greenline has been a leader in the diesel-electric hybrid and solar powered yacht space for years. An ecological landmark among yacht builders, Greenline combines both traditional and innovative technology in their hybrid-drive systems. The Greenline Hybrid yacht line is currently available in eight different models, including the sleek NEO sports boat, the family cabin cruising 33, 39 and 40, and the 45 Fly, 48 Fly, 48 Coupe and the 65 OC. All of these models achieve industry leading fuel efficiency.
Nautique Super Air GS22E
Nautique is currently the only dedicated watersports builder around to offer a 100% electric model, the GS22E. Utilizing an Ingenity drive system, the boat delivers two to three hours of watersports per charge, and can be recharged in as little as 1.5 hours with a DC fast-charge system; AC systems require a 12-hour charge. See Nautique GS22E electric boats for sale on BoatTrader.
Pure Watercraft is a manufacturer that created a 24’7″ all-electric pontoon boat in collaboration with General Motors. It can be had with single or twin 25-kW Pure motors, and gets its supply of power from a GM automotive battery pack. Projected top speed is 23 mph with twins (14 mph with a single) and the boats are currently available for pre-order.
Silent-Yachts is building what the company calls the first-and-only fully solar-sustainable, oceangoing, production yachts in the world. These innovative boats are designed to be powered completely by solar energy alone, offering a revolutionary alternative clean energy solution. The company claims its special configuration of components guarantees that solar panels will generate more power on an average day than the total consumption for propulsion at cruising speed. The boat builder also touts that all household appliances can be powered by the solar panels, requiring no additional diesel or generator to operate.
Soel Yachts, a Dutch company, builds solar and hybrid vessels including marine shuttles. The Soel Cat 12 looks a bit like a pontoon boat with a solar array on the hardtop, and carries up to 16 passengers. Powered by twin 30 kW electric motors, the model can cruise at at eight knots for six hours solely on stored power. In sunshine, the cruising range is extended to 7.5 hours at eight knots. At six knots, the range goes to 24 hours (and approximately 150 nautical miles) so the boat can run at night when no energy is produced or stored. The maximum speed is 14 knots. Their newest offering is the Senses 62, a solar-electric concept yacht.
Solliner, located in Lithuania, builds a single 21-foot catamaran model which can operate on pure solar and/or battery power. The motor produces about five horsepower, and can reach speeds of about seven mph. See Solliner electric boats for sale on BoatTrader.
Fuel Efficiency in Hybrid Boat Engines
In a hybrid solution, there’s still a need for some form of combustion engine (for primary propulsion or as a generator). Increasingly, traditional diesel engine manufacturers have focused on improving the fuel efficiency of their engines in both inboard and outboard applications and they’ve become an ideal partner in hybrid approaches. It seems the whole world is trying to ease up on their carbon footprint even if they don’t eliminate it altogether.
Hybrid and Electric Solutions for Sailboats
Large sailboats are under auxiliary power often, especially when docking, anchoring or heading out on long windless passages. Distance cruising sailboats have pioneered solar power solutions for onboard energy needs for hotel loads such as refrigeration, A/C and lighting. However, propulsion has been a challenge. In 2010, production catamaran builder Lagoon experimented with a diesel-electric design but there were challenges, primarily due to insufficient energy storage (battery) capabilities at the time. Lagoon builds the lion’s share of sailing catamarans in charter that are based in exotic locales where fuel is at a premium and a hybrid solution would be a game changer for the charter industry.
Inboard motor maker OceanVolt powers all manner of sailboats including sailing racers, luxury daysailers, and boats that are often seen in charter. Meanwhile, Torqeedo’s Cruise outboard series includes models with a throttle control and a GPS-based battery-management system that continually reports the remaining range at variable speeds and requires only two 24-volt lithium-ion batteries. These outboards are well suited to smaller, lighter sailboats for close quarter maneuvering and short distance motoring but powerboats have benefited as well.
The newest electric propulsion for sailboats includes a Sail Drive pod unit from Torqeedo. But a new player in the field, ePropulsion, has also begun to target the sail market. Their latest outboards and sail pod drives (three, six, and 9.9 horsepower) have hydrogeneration capabilities, allowing the user to recharge the batteries while under sail.
The Future of Hybrid and Electric Boating
The technology may be complicated and the adoption rate may still be slow, but change is happening at an accelerating pace as breakthroughs in battery capacity, motor design, and lightweight hull-building materials are introduced. Even the giants in the world of internal combustion engines are following down this path; in the past year both Mercury Marine and Yamaha Outboards have announced new electric propulsion units to be built under their banner (a five-horsepower outboard in the case of Mercury, and the 9.9-horse Harmo propulsion system from Yamaha). Fast, clean, quiet and price-effective electric, hybrid and electric boats will soon be within reach of boaters everywhere.
Editor’s note: This article was originally published in May of 2019 and was last updated in March of 2022.
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