Re: [PSUBS-MAILIST] Onboard compressor?

["Greg Teiber" <wolfe19@megsinet.net>]

Well as it comes to a small compressor... it's not so much size, it's the pressure it can develop.  With a small genset you can run a pretty significant compressor.  To do anything usefull in a usefull amount of time we're talking 12-24hp genset for recharging and filling of compressed air tanks.  Most gensets are already setup to vent their fumes in a productive way.  The only real special proceedures I'd follow for installing one in a Psub, is that it should be behind a firewall, and that firewall should have a one way air valve on it.  The genset should ONLY be operated when the hatch/vent/snorkel is open to allow the genset to inhale the large amounts of air a engine will use.  The Genset would act as it's own compartment ventilator, sucking all the available air out and making sure fresh air comes into the boat.  Oh yes, make sure this genset runs on desiel, I don't want anyone blowing themseles up from a gasoline vapor explosion.  The exhaust system for a setup like this would be interesting... it would need to be sealable, and ventilate to some place above the water line.

The compressed air tanks would only need to be filled to a pressure of ~200psi or so, And that simplifys things greatly. Your average shop compressor will hit 225psi.  As stated earlier 3000psi compressors cost an arm and a leg.  As soon as you got a LITTLE air into the balast tanks, the boat would start to rise, and then the ambiant pressure would decrese, and the air that you DID put into the tanks would expand.  So 1cf of air that you put into the balast tanks at 200psia would become 13 cf of air at the surface.  when you're on the surface you can just plug the holes in the bottom of the balast tanks and pump the water out conventionally.  That is as opposed to blowing them empty.  Of course a 3000psi scuba tank would be kept on hand just to do an emergency blow of the tanks... and for maintaining cabin pressure and 02 fraction.

If you are using a scrubber, the amount of air you need to store in tanks is minimal.  IIRC a 2cf pony tank of o2 will keep one human well supplied with air for 8-12 hrs.  If you carry an 80cf scuba tank full of o2, you'll be pretty much set :)  I'd be more worried about scrubber material than o2 supply.

then again this whole discussion gets into the whole submarine self sufficancy thing :)  I offered earlier about scanning then posing my drawings to the list.... they are finished enough that someone MIGHT be albe to get some idea as to what i'm getting at... I'll happily scan them for whomever wants a copy.  I'll need YOUR e-mail address, and I KNOW I'm gonna get a lot of questions :)  so understand I'm prepared for whatever you can give me.

*********** REPLY SEPARATOR  ***********

On 6/25/00 at 6:44 PM S W wrote:

>I guess I was picturing a pSUB large enough to house a
>small engine, like a 2.5 hp Briggs and Straton. While
>surfaced, it could power the sub and recharge the
>batteries with an alternator and atleast partially
>refill an air tank. Perhaps the engine would be housed
>in a seperate compartment isolated from the rest so
>that any cabon monoxide that was produced would be
>vented out. It is a cool idea anyway. Any opinions?
>
>
>__________________________________________________
>Do You Yahoo!?
>Get Yahoo! Mail - Free email you can access from anywhere!
>http://mail.yahoo.com/