Re: Trolling Motors

[Subscuba@aol.com]

Hello Richard,

I talked to a design engineer at Lake Motors located in , I think in Chicago.
Unfortunately I didn't keep his name or number, at that time I wasn't on this
mailing. I had to call Minnkota to get his number and I was told by Minnkota
that the Motor I'm using was made by Lake Motors. I don't know if they make
the motor you are trying to use but I would suspect so. The engineer at Lake
Motors was a little reluctant to talk to me and release a lot of data. I think
he was afraid of impinging on proprietary issues. Any way he gave me the
following:

1) The motor shaft is indeed made of stainless steel, the engineer seemed to
think the steel was not a high grade of stainless steel but much better than
the normal rust enhancement steel used on my boat. The problem with making the
motors for use in sea water is that the housing has to be made of a readily
magnetized steel since the housing is part of the magnetic path. This can mean
rust enhancement steel and must be protected from the corroding effects of sea
water by painting. The motors Minnkota offers for use in the marine
environment have a pretty durable coating but still will degrade. They also
have to cover themselves from incurring extra cost by warranting the product
only for their market. If you use their motor as I am doing it will be a
constant effort to prevent corrosion. I plan to keep a lot of grease
(Vaseline) around the motor shaft along with touchups to the motor paint.
Compared to the other problems this is not major unless you let it get too
far. Painting an additional coat or two of a two part epoxy paint would also
help, assuming compatibility with the existing paint. I once heard rumors of a
stainless steel motor but couldn't find a vendor. I suspect I couldn't afford
one anyway.

2) The electronics will be very prone to sea water damage as well you know.
Coating the Circuit Card Assemblies with epoxy will help minimize the problem.
Total flooding will still tend to wipe out the controller especially with
power applied. 

I would be interested in what you may use for your pressure compensation with
a deadband of pressure. I'm not completely happy with what I am doing since
the positive pressure depends on having the SCUBA regulator always at a
lower,deeper, point than my air spaces. What happens when I turn upside down?
Bear in mind I have a Wet Sub as I intend to do small excursions outside the
Sub plus I can easily bailout. Maybe no excursions if some of the critters I
have seen are bold and/or hungry. My maximum design depth is 480 feet and is
limited by my floatation. That's  much deeper than I intend to go.

Good Luck with your Diver Propulsion Vehicle. If you scout around you may find
some divers are not happy with them. There is one individual in Calif. who was
attacked by a Great White and feels the sound of the scooter he was using
played a part in making him bait. He did survive, just had a lot of scars and
stitches. He had an account of the incident on the Internet for a while.

Have fun,

Ken Martindale