Re: [PSUBS-MAILIST]Seals (was Pressure compensation)

["Captain Nemo" <vulcania@interpac.net>]

----- Original Message -----
From: <Subscuba@aol.com>
To: <personal_submersibles@psubs.org>
Sent: Friday, August 18, 2000 11:15 PM
Subject: Re: [PSUBS-MAILIST]Seals (was Pressure compensation)


>
> "Pat, The regulator I use is a simple piston first stage. It does not have
a
> dial adjust. I simply changed the adjust screw in the second stage until I
> had a slight bubbling of air out of the exhaust of the regulator. This
gives
> me a slight positive pressure in the air spaces without loss of much air."

Ah, I see...clever!

 "The regulator is also at the lowest part of the boat. I don't do any
monitoring
> of the set up except to check the tank pressure from time to time. When I
go
> up excess air vents out the exhaust of the regulator."

Automatically?

 "I installed two exhaust valves in series to minimize any water leakage
back into the air spaces."

These vent the air spaces themselves, and are not hooked to the regulator
exhaust?
>
>
>
>
>  ((But I encountered a power loss when I put it in the Nautilus. {SNIP}
hopefully this will solve the problem, and the next time we dive she'll be
developing full thrust.))
>
"That sure sounds like a lot of trouble."

Maybe I made it sound more complex than it is.  All I'm really doing to
correct the problem is mounting the controller, batteries, and motor in
closer proximity (like they are on the stock unit), and extending the
control lever with a linkage rod up to where I can reach it at the pilot's
station.  Pretty simple, really.

"Since I designed my own motor controller, the leads to the pot carry very
low currents and lead length doesn't matter much."

I didn't think it would matter with the stock MK components; but the techs
say they think this is the source of my trouble.  I'm not in a position to
make my own controller at this time; pretty much stuck with the stock unit;
so the easiest remedy is to return the leads to near stock length, and keep
my fingers crossed.
>
>  ((The MK that looks good to me now is the 36VDC, 101#-thrust "Monster"
> (that's
>  what I heard they call it): it's available for sale now, and they had
some
>  pictures of it on their website when I checked it a few months ago.  If
and
>  when I replace the E-motor in the Nautilus, that's what I'm going to use;
>  until they come out with a bigger one, that is! ))
>
> "Thanks for telling me about the 101# thrust, I'll check it out. It would
be interesting to design a motor controller for the monster."

Yeah, I vaguely remember a conversation we had a while ago about
controllers.  Seems to me you might be able to improve on stock MK
performance.  If I get a "Monster", the first thing I'll try is using the
stock units with near-stock lead lengths and see how it goes.  Don't be
surprised if I have questions about custom made controllers in the future,
however!  ;-)
>
"Have fun and dive safe, Ken Martindale"

For sure, Ken; and you, too.  (And despite what the "sub-whuffos" might
think, we CAN do both!)

Have a good one, and thanks for the info!

VBR,

Pat