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Yamaha Goes Electric

The 121-pound HARMO uses a rim drive and impeller to generate 225 pounds of thrust, about the same force as a 9.9-hp gas outboard.


It looks more like a Seabob than your typical outboard, but perhaps that’s because Yamaha’s HARMO electric boat control system is anything but typical. The unit mounts on the transom but it does not have a propeller. Instead, it uses a rim drive electric motor with an encased impeller that acts more like a bow thruster, pulling water through it to propel a boat.

Coupled to a 48-volt power supply with a 3.7-kW motor, HARMO produces 225 pounds of static thrust, roughly the equivalent power of a 9.9-hp gas outboard. Run times and top speed will vary depending on the vessel HARMO is propelling, but a Yamaha representative said he ran HARMO at low trolling speeds for 7 hours in a freshwater fishing boat with no problem.

HARMO can be run as a single engine on vessels up to 21 feet or used in a twin configuration to push boats up to 32 feet, according to Yamaha. Some suggested applications include tenders, pontoons or even as a kicker motor on fishing boats. Yamaha said it is working with its boatbuilding partners to better understand how they see HARMO finding its way onto more transoms.


The system also features Helm Master EX controls and integrated Digital Electric Steering, so you can steer the engine with a traditional wheel or a joystick. All of the turning is done below the waterline and the drive turns a wide 140 degrees. You can completely rotate a single-engine boat in a single boat length, and with twin HARMO engines you can walk the boat sideways using the joystick. The motor can tilt up to 74 degrees to keep the impeller out of the water when not in use.

HARMO is completely silent. So quiet in fact that Yamaha’s Phillip Speligene said you have to put your hand on the motor to see if it’s running. This system is currently only available through boatbuilders in European markets, but we should start seeing it stateside in 18 months.