Sunday, December 04, 2011


It's that time of year when I look back on how my electric propulsion system did during the past season. Once again I was surprised by it. When I decided in 2007 to repower with an ASMO MARINE Thoosa 9000 system. There were no boats that I knew that had done this and I thought long and hard about it before making the leap. But, after four years of operational experience I'm still very glad I did. The fourth season will stand out because of two firsts that occurred. One was an extended day of motoring. About ten hours to be exact. A rare day here around the Isle of Long when hardly even a whisper of a breeze filled the sail. So after starting out early and motoring under battery power for a few hours I carried the Honda away from the cockpit and fired it up. I could never do that with the old diesel. The noisy diesel was always right below the cockpit vibrating away making for a noisy afternoon of motoring. Fatiguing too! My day of extended motoring was much more pleasant experience with electric propulsion.

Another first I discovered quite by accident was that BIANKA can actually regen power back to the battery bank. I discovered this while electro sailing moving along at about 6 knots. I had earlier in the season decided  that the best way to operate  under sail was to slightly turn the prop under power. This will negate any prop drag when sailing and therefore increase boat speed. Sounded like a good plan and it uses minimal power from the battery bank and no need to buy a folding prop. But, as I found out that if the boat speed under sail starts touch around 6 knots it also starts recharging the battery bank.

 This is known as "regen" where the prop starts to turn the motor backward and it starts operating as a generator. It's not a lot at the low end but, you really don't want a lot charging because you don't want to take a chance on overcharging the battery bank.  I'm looking forward to next season and hope to experience more days where I can see the regen in action. So even after four years my boats electric propulsion system still had some pleasant surprises left to show me.


Skip said...

My conversion with an electricyacht 260i is almost complete.I look forward to comparing my experience with yours.

Capt. Mike said...


I hope you have as much joy with your conversion as I did with mine.