One more thing. The void space between seals will need to be oil filled so that the inner seal has something to run in. If that one leaks, you'll know it pretty quick.
What about doing the right thing up front and installing two seals in line with support bearings in the housing? Then this entire thread goes away. Install a fitting between the seals and run a small pressure gauge on a 1/8" hard tube to wherever you want it. If the outer seal fails you'll see the flooding internally. Then you don't have the issue of dinging a prop and knocking your shaft minutely out of line which would jam the works. I've put about a zillion hours on a shaft seal package like that and never had the first moment's trouble.
Vance
-----Original Message-----
From: James Frankland <
james@guernseysubmarine.com>
To:
personal_submersibles@psubs.org
Sent: Tue, 26 May 2009 6:48 am
Subject: RE: [PSUBS-MAILIST] Precision prop shaft
Hey all.
i thought of an idea for sealing a leaking through hull.
What about machining a very fine taper onto the outside of the shaft. Then
threading the inside of the shaft after it exits the through hull and fitting a
wing nut and spacer? Then if the seals leak, you could screw down the wing nut
which would pull the taper into the gap and jam it shut?
What do you think? Would pressure push the taper in anyway under normal
conditions? im thinking of doing this for the drop lead controlls, variable
controll and rudder.
Regards
James
----- Original Message -----
From: Smyth, Alec [mailto:Alec.Smyth@compuware.com]
To: personal_submersibles@psubs.org
Sent: Mon, 25 May 2009 21:30:02 -0400
Subject: RE: [PSUBS-MAILIST] Precision prop shaft
There shouldn't be friction, the shaft rotates freely. I do however plan to
leave it out in the sun on the driveway when we get some good hot days, just in
case hot temperatures are an issue. Though in the water that would be rather
unlikely.
________________________________
From: owner-personal_submersibles@psubs.org on behalf of Jon Wallace
Sent: Mon 5/25/2009 8:42 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Precision prop shaft
Nice job Alec. One question I have given the close tolerances. I
wonder if friction caused by rotation of the shaft will cause expansion
of the shaft such that it binds or locks up. Any thoughts on this?
Jon
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