EPROPULSION NAVY 3
 
Epropulsion's Navy 3 is a direct-drive 3kW electric outboard - like its smaller sister, the Spirit, there's no gearbox - making it delightfully quiet and responsive. Technically, 3kW translates to only about 4.5hp, but with much, much more torque than you get from a 4.5hp petrol motor. As this torque also comes instantaneously (rather than at higher revs, as with a combustion engine), it has an incredible amount of "shove".  
 
The Navy 3 is thus ideally suited to pushing along surprisingly large boats at displacement speeds. During the Summer of 2019 we've had one on the back of a Swallow Yachts Bay Cruiser 26 - about 2 tonnes, achieving a top speed of about 6 knots - and a Jaguar 27 - about 3 tonnes, achieving a top speed of about 4.5 knots. With sufficient battery capacity we'd say that's a viable alternative to fossil fuel burners, certainly for the 2 tonne yacht. And that's if you're just thinking about it in terms of replacing a combustion engine. It's no exaggeration to say that we think an electric motor is so much nicer to use than a petrol or diesel one, it will change the way you use the boat. You notice the complete lack of noise first, and not long afterwards the lack of vibration (that you used to live with, without really noticing). The big implication of this is that when the wind drops off you can apply a few hundred Watts and keep on enjoying your day "electric motor sailing" - rather than dropping the sails and firing up the noisy smelly type of engine to get to your destination as soon as possible. (Applying even 3-400W of electric power will point you up at least 10 degrees higher and a knot faster.) Keeping the sails up longer means you use less fuel (whether that be electricity or petrol or diesel) overall, and massively extends the range potential from a finite battery supply. Furthermore, running an electric motor under light load doesn't do it any harm, unlike a diesel (glazing of bores etc). For the cruising sailor hybrid electric-sail drive will be transformational.
 
The Navy 3 can also be used on smaller craft of course, and will for example push a 3m dinghy with four people on board along at about 8 to 9 knots (10 knots maximum on an easily-driven, light hull). What it won't do though, like the Spirit, is get boats on the plane. The shaft speed and propeller are not designed to achieve the higher speeds necessary to plane, they are optimised to use all that torque in the most efficient manner possible.
 
Please note that the standard price for the Navy 3 is for the motor only, so you need to add either a tiller or a remote control unit, and at least one 48V battery (or four 12V batteries wired in series). Ignoring cost, lithium batteries such as the Epropulsion Navy battery offer by far the optimum solution in terms of power delivery, storage size and weight. In terms of run time, each Navy battery will give you just over an hour flat out, or 3hrs at 1kW output (capacity is 3042Wh).