
11-14-2008
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Gemini 105Mc Hull 987
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Join Date: Sep 2007
Location: Annapolis - Cape St Claire
Posts: 4,212
Rep Power: 7
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I don't know SD, I tend to take them on faith when they say that an electric motor has full torque at 1 RPM, and it's torque that moves the propeller not HP and because of that the boat only needs 1/2 to 1/3 the horsepower when compared to a diesel.
That said, the chart at the link shows 65 amp's (3120 watts) or 4.1 hp pushing the Islander 28 test boat (7000 pound displacement) at 5kts. With 220ah of batteries on board..make that 8000 pound displacement.
Maybe they have something there, maybe not. I don't have an Islander 28 to test with a 4hp outboard.
Of course, real world independent testing has proven otherwise.
We'll purposely skip the fact that they say 3 hours of use to take the battery to 80% drained because no good skipper would KILL his batteries that way.
dang it, I was going to stay positive..
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