Choose Electric – The Best Propulsion System for a Sailboat

Electrification of sailboat propulsion systems is a trend that we’ll see continue to grow rapidly over the years to come, and it is occurring for several reasons. The advancement and prevalence of high-quality, safe, and energy dense batteries is a technical reason that now makes electric propulsion practical.

Electric propulsion also just provides a better overall sailing experience, while being completely clean, so much better for the environment.

Like a camper or RV, on a sailboat you cook, eat, relax and sleep inside a relatively small space setup with as many creature comforts as possible to add to the fun. Unlike a camper or RV however, the engine is located INSIDE rather than OUTSIDE of this relatively small living space. While the engine compartment on a sailboat is always equipped with a ventilation exhaust system, and there is much care taken to seal engine exhaust from getting inside the boat, odors from the diesel engine are inevitable.

This is especially true on older boats, and not necessarily because the engine exhaust is leaking (although that certainly can happen), but because after years of running and cycling between very hot and cold states, small leaks do occur. Over time, fuel, oil, and exhaust leaks in and around the engine accumulate and inevitably, when the deck hatches aren’t open to allow airflow through the boat, everywhere below deck smells like the inside of a mechanics garage.

When a sailboat use electric propulsion, all of those smells, as well as the noise of the diesel engine running, is eliminated. Also, when using electric propulsion, the number of moving parts for propulsion is minimal, which practically eliminates any motor maintenance issues.

For example, the NEB-25 system (Newport Electric Boat’s 25 kW motor, with power equivalent to a 34 HP diesel) uses a AC Induction motor coupled to a gearbox that transfers the torque from the motor directly to the propeller. The motor is brushless and highly power efficient. Speed and direction is controlled electronically, so forward and reverse thrust is precise and instant, which makes controlling the boat easier. This is especially noticeable when maneuvering the boat into a slip or up to a dock.

As for the environment, electric propulsion couldn’t be cleaner. There are never any fuel spills to worry about. There is no exhaust bubbling up at the stern of the boat, and there is no noise pollution from a running engine. The only fluid in the entire system is a small amount of gearbox lubricant (less than a liter), which go’s for years without ever needing attention.

On a diesel sailboat, it is typical (required) to have stickers posted on the inside and outside of the vessel giving warnings about the dangers of breathing carbon monoxide in confined spaces. Clearly the industry has had problems in the past with toxic fumes that lead to requiring these signs to be installed by the sailboat manufacturers.

Older sailboats with a diesel motor now have viable options to go electric. The NEB-25 is a drop-in replacement for the most common inboard diesel engines, with the same footprint and shaft coupling as the Yanmar 20HP and 30HP engines. This allows sailboat owners who want to upgrade to electric, to go through a straightforward conversion process, to remove an older engine, and replace it with a modern electric propulsion system.