Fin5, a jellyfish for engine

FinX’s Fin5 is an electric outboard, has a power output of 2 kW, which corresponds to about 5 hp, and is powered by a 48-volt battery

by Niccolò Volpati

Nothing unusual, especially these days. Mets in Amsterdam is full of booths offering electric outboard motors. What makes Fin5 something different from all the others is the propeller, or rather, the absence of a propeller.

The thrust comes from a membrane mounted on the end of the foot. The motor makes the membrane move, which mimics the thrust that a jellyfish usually makes when it swims. It does not have a reverse gear, but by rotating the shank you can position the membrane exactly on the opposite side, thus being able to reverse the direction of travel.


Fin5 is designed for boats up to 3 tons, but FinX, the French company that developed it, plans to make other thrusters with higher power ratings. After four years of research, the prototype has moved on to actual production, and the first models will be available in the coming weeks.

With the 48V battery, Fin5 provides one and a half hours of range at full speed and six hours at cruising speed. The only drawback is that the battery is not integrated and therefore must be placed on the floor of the tender or boat near the engine. In fact, the cables that are used to run the outboard are connected to the battery. This is not a difficult operation, and you do not need to be an expert to do it because it is all easy and intuitive, but unscrewing the terminals of a battery and carrying it to recharge it is still not a very smooth operation.

More information can be found at

(Fin5, a jellyfish for engine – – November 2023)