RE: [PSUBS-MAILIST] re-wiring trolling motors?

["Ron Leonard" <ronleonard@home.com>]

As you know Pat, we have been using MK motors in our SportSubs for over 10
years.  If you flood them, they are OK so long as you drain them, rinse them
with kerosene or something like that, and dry them out.  With an ambient
pressure system like Herve has described, and that we also use, they should
not get water in them. With regards to their reliability compared to MG, we
haven't done any testing as we have not had problems with the MK motors and
their ability to deal with moisture or water so have not felt the need to
look for other motors.  I should add that we have had the magnets release
from the case on a few occasions and that they have been fixed under
warranty. It seems Herve has had some problems with MK motors and moisture
and has done some testing so we will have to defer to him. If he says MG are
more water resistant, then they probably are, I don't know.  Also, the MK
motors have composite shafts now, isolating the motors from the rest of the
vessel if you use the shafts for mounting. Mounting an anode on the
composite shaft, or the vessel will do you no good in this case.

Ron


-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org]On Behalf Of Captain Nemo
Sent: November 25, 2000 8:24 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] re-wiring trolling motors?



----- Original Message -----
From: "Herve Jaubert" <caribsub@coqui.net>
To: <personal_submersibles@psubs.org>
Sent: Saturday, November 25, 2000 7:54 PM
Subject: Re: [PSUBS-MAILIST] re-wiring trolling motors?


> Alec,
> Where did you put the sacrificial anode?
> When you purchase a Salt water motor, the anode is usually on the shaft, I
> mean on the column that goes through  the motor body.
> But you have to control with an ohm meter that you read "0" between the
> sacrificial anode and the propeller AXLE ( I said shaft in my previous
> message, sorry).
> All motors should have continuity between the anode and the Stainless
steel
> axle prop.
> I noticed that only 30 % of the motors have continuity, that means that
most
> of the owner of salt water motors think their motor is protected against
> galvanic corrosion when they are not.
> It is because the body of the motor is in 3 parts and when they are
> assembled, probably some coatings make a break in the continuity between
the
> body parts.
> That is why i put an additional anode, a small one , on the little fin of
> the motor, that way all the motor is protected, axle, bearings, body, and
> shaft.
> It is actually simpler than to rewire the motor. (disassembling required)
> This procedure is important, otherwise under frequent use your motor will
be
> galvanic corroded.

Hi guys,

Well, this is all very interesting and pertinent to what I'm doing right
now.  Today I chopped my motor mount and cut a couple inches off the
NAUTILUS pressure hull tailcone to accomodate a new Minn Kota RT 101/S.
(That's the transom mounted, salt water variant). Thanks for the tips on
Motorguide, Herve, but it's too late for me to change now!    ;-)

The comparable Motorguide unit had about 6 more pounds of thrust at max
output, I think; but I verified what Alex said about part of the controller
on the Motorguide being in the lower end unit (the MK is all in the hand
controller, which will be inside the pressure hull with me), and I thought
that might have some advantages coolingwise, so I went with the MK.
Admittedly, I haven't actually run either the MK 101 or the MG 107, but I
had to decide on something, and that's the way I went, based on what I
understood at the time.  Even if it's not the best, it's gong to be a lot
more motor than I had originally, so it won't be too bad.

I may be wrong about this, but I think the tech said the MG 107 didn't have
built in reverse (bow mount); so I would have to incorporate another
controller.  As I recall, that was another factor in the decision to go with
the MK which has reverse built in.  Was I wrong about this?  These are the
newest motors on the line.  Anybody know for sure, just out of curiosity?

About corrosion: since I'm operating in salt water, this is VERY important
to me.  Interested in what you said about placing the anode on the shaft
between the lower end and the controller unit, Herve.  I'm running WITHOUT a
shaft.  (The controller is in the cockpit; the wires go out through a
watertight coupler; and the lower end is mounted outside in a custom-made
free flooding steel mount.  The MK transom-mount and shaft go in the scrap
pile.)

I'm thinking the anode should go outside on the motor mount.   Or maybe
attached in some non-destructive way to the outside of the motor case?
Whatayathink?  (Oh, BTW; I can't hang it on the little fin, because I have
to cut that off to fit in the tube-shaped motor mount.)

I want to do all I can to ensure good corrosion protection, because I'm
operating in the ocean, and I don't want to keep pulling the motor out after
every weekend of diving.  (Although if it comes to that, I'll just install
some watertight connectors in the wiring harness outside with the lower end
unit, and pull it apart as often as necessary).

Anyway; thanks for the good tech talk; and this comes at just the right time
for me.  Any ideas would be greatly appreciated.

BTW: glad I decided to also repack all the control-shaft glands; the rudder
was leaking.

I'm videotaping the refit in progress; and if Ray wants to post some scans
of the humungous roller mount and other things I've made to do this
overhaul, I could make some JPEGs with my video digitizer and send them in.
If there's any interest, I'll do it.

The overhaul is including complete rework of propulsion, guidance,
dive-plane controls, life support, and exterior detailing.  Been making the
salon window fairings, rigging all the lights, got 12,000 simulated rivets
underway; and coating everything with resin to resist rust.  Film shoot for
the DISCOVERY CHANNEL show is slated for late January; I'm figuring to put
her back in the water at Hilo some time in December, to make sure the weight
and balance is tweaked correctly.  I'm adding some weight in systems; losing
some weight in extra ballast I had to carry to compensate for the missing
passenger; and with the added buoyancy of sea water, it looks like it's
going to be about right.

Film at eleven...

OH BTW: PHIL: if you're reading this: thanks for the magnanimous FED EX
offer; you're the best.  But I found a local supplier working rebreathers
who has a wholesale contact for SODASORB, so I'm doing alright.  Thanks
again!

Gotta go; been a long day, and I must have gotten about 10,000 new nicks,
cuts, and burns today.  Time for the rain room, the hot tub, and a cold one.
(People who don't do this sort of thing will never know what it's really
like; and those who know will never question why submarines cost so damn
much!  Everything is paid for in flesh!)

Ya gotta love it!

;-)

Pat