Re: Trolling Motors

[Subscuba@aol.com]

Paolo,

For what it's worth. The trolling motors are basically shunt wound motors made
for constant speed, loading the motors down with another propellor  may
excessively load the motor and degrade it's life. The high RPM you mentioned
may be necessary for motor life and maximum motor use. I'm under the
impression that in the marketing race of thrust versus motor size and cost
that the trolling motor propellors are matched for the maximum thrust
consistent with motor loading in a static environment. This probably changes
when you are at speed but maybe not much. Have you performed any tests on the
problem of thrust versus propellor and motor loading? Were you able to get any
data from Motorguide on this subject? I think they make a propellor called a
"Ninji" which is a three bladed propellor.

I like what you said about the two seals on the Motorguide, that should be
better than the Minnkota. I have considered placing two cup seals on my
Minnkota. It looks like there is room but I haven't tried it. The Minnkota
appears to be a more powerful motor from what I have found out.

I once worked on D. Rebikoff's Pegasus and he used a ceramic seal which he
said was in common use in the water pumps used on wells. The kind you find in
Wal-Mart at about 1 HP. He showed me one and it looked like two rotating
ceramic washers spring loaded and static O-Ring sealed. he said these seals
lasted a very long time with few problems and were good for high pressures, at
least several hundred to a 1000 feet. He is still around and can be contacted
if anyone is interested.

Have fun,

Ken Martindale