Re: Thruster Construction

[Subscuba@aol.com]

Steve,

I would think you would need someone who could do a thermal analysis for you.
My opinion is that if you had good thermal contact between the steel pipe and
the motor housing the surrounding sea or fresh water would provide a more than
adequate sink to prevent the motor from overheating. If the motor is made to
run in free air you may have a safety margin for cooling. The answer is not
simple since the cooling depends on the construction of the motor. Some motors
are made with forced air cooling and do not conduct much heat through the side
walls. If this is the case you may have a problem.

I estimate the motor at 12 horsepower draws 270 amperes from 36 volts assuming
92% efficiency for the motor, almost 10KW of power.  I'm interested in what
size your batteries may be  to provide this kind of discharge current. If your
batteries are sized to provide more than a few minutes of operation your Sub
must be fairly large. My question is what size is your Sub? 

Good Luck and have fun,

Ken Martindale