Re: [PSUBS-MAILIST] Thrust from a pump?

["Rick and Marcia" <empiricus@telus.net>]

Ok - not too bad.  If you're not using pumps to fight current, just for
static maneuvering, consider using bilge pumps that've been compensated.
You'll need the more powerful ones.  In the Winter 2006/07 issue of
BoatWorks, there's a bilge pump showdown.  For $41 USD you get an actual 540
gal/hr (9 gal/min, and that's with a 5 ft. head), the Attwood V900.  Draws
2.4 amps.

Again, it may be ok for backing off a wall, hovering or yawing for that
perfect shot.  Especially if you have a significant moment-arm (lever) like
the tail rotor of a helicopter.

Cheers
Rick L
Vancouver


----- Original Message -----

Subject: RE: [PSUBS-MAILIST] Thrust from a pump?


About 4,500 lbs

________________________________

From: owner-personal_submersibles@psubs.org on behalf of Rick and Marcia
Sent: Thu 1/4/2007 10:42 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Thrust from a pump?



Alec, regarding water pumps, how heavy is your sub?


----- Original Message -----
From: "Smyth, Alec" <Alec.Smyth@compuware.com>
To: <personal_submersibles@psubs.org>
Sent: Wednesday, January 03, 2007 2:20 PM
Subject: [PSUBS-MAILIST] Thrust from a pump?


I'm contemplating using water pumps as maneuvering thrusters (NOT for
main propulsion). Cousteau's socoupe used a hydraulic pump for the jets,
but I'd like to avoid that route if possible due to the excessive noise.
DC submersible pumps are convenient but I haven't found anything beefy.
I could try mating a trolling motor to a pump head. Submersible well
pumps look promising because they're very powerful yet compact, but they
require AC, and I don't think I can reverse them so I'd need four pumps
instead of two. I could of course hang trolling motors off the boat font
and back, but it really messes up the hydrodynamics of what can
otherwise be a quite clean design, and the props on my trolling motors
make them too large to duct into the MBTs.

Assuming I do settle on some kind of pump, the next question is how
strong it needs to be. Does anyone know how to translate GPM (or LPM)
into static thrust?

Any ideas or experiences would be much appreciated.


Thanks,

Alec
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The contents of this e-mail are intended for the named addressee only. It
contains information that may be confidential. Unless you are the named
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it to anyone else. If you received it in error please notify us immediately
and then destroy it.





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603-529-1100
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