As in other fields, technology applied to electric motors is evolving in the nautical world: the newly introduced regulations lead, for navigation as elsewhere, to the choice of engines with this type of propulsion.
However, it is necessary to understand up to which point the technology is ready to move small and medium-sized boats in particular: we are talking about outboard motors, made for moving boats of not extraordinary dimensions.
Therefore, it’s useful to take into account that the total weight of the batteries can be higher than that of the tank of a combustion engine, moreover there are some limits to take into consideration and which we will discuss later. The most recent models on the market are rebalancing the parameters of comparison: we can then make an overview of the state of the art of electric outboard motors.
So let’s begin to evaluate the main advantages and disadvantages of this type of technology applied to boats.
Electric outboard motors: strengths and weaknesses
The comparison between combustion motors and electric motors ones is certainly interesting, in particular in the nautical sector.
The main point in favor of an electric outboard motor is that it does not pollute the waters where it operates: this allows to have access to sea areas and lakes where combustion engines are now prohibited. Moreover, this type of engine guarantees an extremely low level of noise pollution, with all the related advantages for the surrounding fauna.
From a mechanical point of view, it should be considered that the maintenance required for electric motors is almost zero, unlike the combustion ones.
Also longevity is generally much higher: the electric propulsion unit is generally lighter than the combustion counterpart and this leads to a definitely lower life cycle cost of the electric outboard motor.
Current limitations of this solution
We find one of the starting points against this engine at the time of purchase, in fact the initial investment is certainly greater, but this initial expense is fully compensated by the reduced maintenance costs.
The second point concerns that of autonomy, a classic issue also in the case of electric motors for cars; however, it must be said that the new technologies have allowed significant progress. Consequently, for a classic occasional use and for not particularly long distances, there are no more problems.
In any case, the batteries have a heavier weight than the counterpart of a combustion engine fuel tank, and also the time to recharge the battery is much higher than the necessary time to fill the tank with fuel, therefore, in the case of longer journeys, it’s a good idea to carefully plan the route and stop times.
New improvements of electric outboard motors
The first models applied the same structural design as the combustion units: the engine was housed inside the grille and the torque reached the propeller via indirect transmission. This way, all the classic problems of energy dispersion typical of this type of unit were present.
The new models, on the other hand, have moved the drive unit under the surface of the water with a direct transmission to the propeller: this modification allows maximum efficiency and minimum waste.
Furthermore, the space inside the grille has been freed up to house the new lithium batteries; these are able to store more energy and recharge more quickly.
However, it should be noted that for longer journeys it may be necessary to equip the boat with additional batteries.
Available power and autonomy
We are now going to talk about two other parameters which are closely linked.
The electric outboard motor starts from models created to move small and light boats up to those of really important power.
The advantage of electric units is that they are born to make the most of maximum power, this is usually difficult to replicate on combustion engines due to wear and overheating. For models of this kind, the standard setting uses approximately half the power.
The outboard models with electric propulsion range from a minimum of 1 HP up to 80 HP. As we will see shortly, the electric outboard motors are designed for an autonomy ranging from one hour up to even 5 hours.
An interesting Torqeedo model for small boats
Among the various available options from Torqeedo, there is an example of a motor expressly designed for tenders, small sailboats and small boats for rivers and lakes. Torqeedo Travel 603 is an electric outboard motor that weighs only 15.5 kg and delivers around 2 HP. As for autonomy, proceeding at moderate speed, it can also reach 5 hours of autonomy: a perfect solution for small boats that don’t need other performances.
The future of the outboard motor is electric
The electric evolution proceeds swiftly also with regards to navigation: the Torqeedo models provide adequate power with an autonomy that is always outstanding. Furthermore, continuous research leads to higher innovation that allows to constantly increase performance and autonomy, without forgetting about the elimination of polluting emissions in the water.