Having sailed half way with an electric engine, I have to say it has been a great experience. Yes, there has been some unfortunate issues in my case (hydro generation), with the shifting of versions of engines and updating batteries, gateways, displays and other "power intelligence gadgets". But I assume that it is part of the game these days when adopting new technology. The most important job for the drive is obviously to push the boat when needed and in that field my silent friend under the hull has been, and is, doing a great job.
OK FOR SHORT RANGE MANEUVERS?
By now I have tested it for short ranges some 90+ times in and out of marinas, up against rivers, when passing opening bridges or canals and when settting sails in no wind and in strong winds.
It was a little "scary" to begin with as the engine does not make any sound when turned on, but not yet running – like a fossil fuel engine does. Meaning there is no comforting sound from it when letting go of all the moorings in windy marinas... But after checking that the two indication lamps on the display are green, I have learned to trust that it always start when needed. And the direct propulsion is fabulous. It moves my boat exactly as I expect it to do. I feel much safer with this new "exact power" than with the moody inboard gasoline engine from earlier years...and of course far more safe than from the days when we had an outboard engine hanging on the back.
The direct torque is a blessing on a boat where everything else is not – wind, waves, current other boats and it is really reliable in tricky situations. The silence is wonderful, people can hardly hear it and some think I am sailing in and out of marinas like it was my profession haha.
I have made short random notes from every in-and-out of the marinas and I will publish them in a list eventually.
POWERFUL ENOUGH WHEN TOUGH DEMANDS?
The former engine was a 10 hp gasoline engine. My boat Johanna is a 34 foot long, 2,2 metres wide and her displacement is some 3,2 tonnes. The draft is 1,7 metres with a classical fin keel. The keel is placed pretty much aft of the center and the proportionally long hull up front is very shallow. That makes the bow an easy victim for side winds in tricky marinas. The direct propulsion takes care of that in a great manner as it easily kicks the boat around with its exact and direct power. I usually do marina maneuvers really, really slow (trusting the boat's weight) so I have never needed to use maximum power to solve any serious dramas so far.
I have tested almost full engine speed up against 1-2 meter waves, 2-3 knots current and winds up to 20-25 knots. It works fine and I never felt insecure. The only worry has obviously been concerning the range. Going in high speed no matter the conditions reduces battery capacity fast of course. Range is a mind game – apart from being a security issue – it is also an individual issue, meaning you learn to handle it as you get to know your own electric engine and its capacity in your own boat. The mind game part has made me chill out longer and rely more on my sailing capacities. Meaning setting sails earlier and taking them down later. That is where sailing should be, right?
TEST: DOING 3 KNOTS IN 30 MINUTES – USING 5%
I wanted to get som capacity figures easy to remember. So I have tested the following three times on open and fairly calm water (on the leg Kiel - Rødby): I go in 3 knots for 30 minutes in order to see how much battery it eats...and in all three cases it was 4-5%. Nice, I can easily hold on to that result and use it for upcoming estimates.
I will do the same test in 4, 5 and 6 knots in 30 minutes chunks later on.
TEST: DOING 5 KNOTS USING 60% – APPROX 80 MINUTES AND 7,1 NAUTICAL MILES
We also tested to do 5 knots outside of Copenhagen and we deliberately used 60% of the batteries capacity. It took us some 7.122 NM. We had 0,5 knots current partly from aside and varying as we came closer to Copenhagen harbor. The rough range figure to hold on from this test is then: 5 kts, 7 nm eats 60%.
These tests are done between two "cheating charges". One as the new battery was installed and had to be synced and "delivery charged", and then after deliberately emptied them by doing performance tests and using all capacity (we were then using a separate charger from Torqeedo – not breaking my own sealed charger). I will come back with more tests and report more on the hydrogeneration once we have more experiences from that.