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I was looking at some small motors on an auction
site last night.
I guess every different motor would present it's
own set of problems.
Would be fun having a snorkel &
running the sub on outboard just below the
surface.
Alan
----- Original Message -----
Sent: Sunday, February 27, 2011 2:59
AM
Subject: Re: [PSUBS-MAILIST] pressure
compensated outboard
Nice it's all figured out now, now the only thing left is to
build it ;)
On Fri, Feb 25, 2011 at 11:10 PM, Alan James <alanjames@xtra.co.nz>
wrote:
Hi Brian,
Yes, epoxy & you need to try it on the
polystyrene first, as some additives
in some epoxies can dissolve
polystyrene.
Acetone does a good job on polystyrene. Petrol
can dissolve it. It dissolves down to a
hard thin layer. Sometimes flakes of it come
off, so you'd want to make sure these wouldn't
travel anywhere where they're not
wanted.
I was thinking you would need to glue several
blocks made of some heat resistant material
like aluminum, around the motor, flush with the level of the polystyrene, so the fiberglass
jacket
was left suspended around the motor on
these.
A further thought was that you could
calculate the volume of air required to counteract any
buoyancy problems caused by the motor at the
back of the sub. & incorporate this in the size
of the motor jacket.
Alan
----- Original Message -----
Sent: Saturday, February 26, 2011
7:12 PM
Subject: Re: [PSUBS-MAILIST] pressure
compensated outboard
I did think of Frank when thinking of this, maybe he's still
influencing our thought process more that we know ! so you're
saying create a very small amount of an air pocket. Somehow I was
thinking steel, but that really wouldn't matter with an ambient
situation. A fuel bladder would work also. How does one go
about dissolving polystyrene? Actually polyester resin is not
compatible with styrene so you would have to use an epoxy - which would be
so much the better anyway.
Brian
On Fri, Feb 25, 2011 at 7:18 PM, Alan James <alanjames@xtra.co.nz> wrote:
Hi Brian,
there are flexible fuel tanks that have the
advantage in that they would be pressure resistant
& as your fuel level changes your
buoyancy wouldn't change; or not significantly.
You could possibly cover the motor with
thin sheets of polystyrene then fiberglass over it
&
dissolve out the polystyrene leaving a
small pocket of air around it.
I'm sure if Frank were around he'd be on to
this. He wanted to put an outboard on Git Kraken.
Regards Alan
----- Original Message -----
Sent: Saturday, February 26, 2011
3:10 PM
Subject: Re: [PSUBS-MAILIST]
pressure compensated outboard
Hi Alan,
That was my first thought, if any components would be affected.
I can't see where there would be a problem, anything that has gasoline
in it would be safe as far as pressure is concerned. I'm
thinking a 20 hp or so outboard, electric start, fuel injected.
I think most of those are water cooled so that would be a plus.
I would just turn the whole cylinder to steer, and mount the thing in
there good. Have a fuel line that could be valved off, the fuel tank
might have to be pressure resistant.
Brian
On Fri, Feb 25, 2011 at 5:58 PM, Alan James
<alanjames@xtra.co.nz> wrote:
An ambient outboard!
Sounds like an idea with a lot of
potential Brian.
I'm wondering if there are any
components that may be affected by
the air pressure.
How big a motor are you envisaging?
What sort of motor
controls?
Regards Alan
----- Original Message -----
Sent: Saturday, February 26,
2011 12:57 PM
Subject: [PSUBS-MAILIST]
pressure compensated outboard
I have an idea for a pressure compensated outboard engine so
as to give surface power for my sub. Basically it
would be a "can" that would cover an outboard engine with an
opening on the bottom. There would be a float valve located
near the bottom of the opening so when I submerge, as
the water begins to move up into the cylinder, compressing the
air, the float valve would inject air. That way it
would keep a constant volume of air in the outboard engine
compartment. As you assend the extra air would simply expand
out the bottom.
Brian
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