Re: Powering a 12 ton boat; need advice on big DC motors
I can offer no help with the electrical calculations, execpt to sugest a small electric bow thruster auxillery motor up front for steering. They are common here on fishing boats, especially bass boats for tight turning without using the main engine.
Here when a dealer matches a motor to a boat, they take along several props of different pitches and test to find one that allows the engine to reach full rpm on the chosen vessel without labouring.
If you can water cool, running copper pipe along and back just above the keel is common and replaces the need for any type of radiator/fan. A small coolant circulating pump would possibly consume less electrical power than a larger air cooling fan.
You have our interest Mark, as the day will come such regulations are enforced here as well.
Larry ( in Southern Ontario )
1976 Ford LGT 165 / Johnson 10TC Loader / 54" Snowpusher.
1973 White Town & Country / 42" Two Stage Snow Blower.
1976 Ford RMT 66 RER / Grandson's first tractor.