Originally Posted by S/V Antares
Configuring the big boat should be straight forward but....What dingy are you using? Batteries? Voltage?
I have the lower drive of a 50 hp outboard
, as you have to size up for the torque of an electric
. The dinghy
will be one of the air entrapment, minimum wetted surface rigid hull catamaran
style. This allows good range at planing speed due to less drag with the reduced cohesion of water
drag. Batteries will be LiFePO4
, capacity somewhere between 80~160 a/hr, (16) in series for a nominal 96 volts.
Since a 40 hp gas outboard
will propel the above dinghy at near 60 mph, I will have to gear
up at the motor head
to compensate for the 1.85 to 1 reduction in the lower unit. I hate the losses of running both a gear
up and a gear down, but don't know how else to do this. On a 50 hp outboard you have a gas engine
capable of 6500 rpm
vs 5000 rpm
of the electric motor
and also you are limited on pitch
for this lower unit, so you can't just pitch
it taller. Of course all available torque at zero rpm will negate any sluggishness on a hole shot.