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Not sure about the battery Brian.
I think wet cells are OK but AGM type
batteries need a bit of work to enable them to
take the pressure.
Was looking at a few motors, & some of them
that have the fiberglass motor covers going
right down over the motor may be able to be used
without enclosing this top section.
The example below has a pull start wich would
be a problem.
You would have your ambient system set up with the float down low, maybe in
just a tube covering the lower section,
so everything above that point would have the air pressure above the water
pressure. This would mean that if the motor
cover seal (wich you may have to beef up) failed it would be letting air
out rather than water in.
With the pull start you could do something like attach a small threaded
plug to the back of the pull handle & a female fitting
on the motor cover that the plug is screwed in to for diving.
Alan
----- Original Message -----
Sent: Sunday, February 27, 2011 11:42
AM
Subject: Re: [PSUBS-MAILIST] pressure
compensated outboard
Do those small outboards have a battery inside? The things
that would have to be worked out are the starter button, the fuel line, the
throttle, steering, air intake ( could be a valve), material to make it out
of. I think just using a hardwood like oak for the structure of the
enclosure and then just fiberglass and epoxy to do the finish
shape. Seal inside and out with epoxy.
brian
On Sat, Feb 26, 2011 at 8:55 AM, Alan James <alanjames@xtra.co.nz>
wrote:
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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