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Having backups is part of good planning, and planning for survival is
more important than planning for diving.
After your high pressure air is gone, or you don't have enough to
raise the inside pressure to within 1 p.s.i. of the ambient at your depth.,
you may need a scuttle valve to save your life.
Two or three small problems, each alone, are easy. Together they
can cause a disaster.
Maybe put a valve on each side so they can't suck in mud? As my hatch is a
top dome, it will have escaping air rising, helping to lift it. Water will rush
in, I will scuba out.
-Peter Korwin
On Wed, 10 Mar 2004 07:57:36 -0800 (PST) irox <irox@ix.netcom.com> writes:
> > For the cost of the scuttle valve (what $100? hell I'll take two at > the price) is it not worth having a backup escape route/plan? > > H.P. air sounds reasonable, but how much air do have on board? How > many times will you try to blow your main ballast tanks at depth trying to free your sub > before deciding to presurize the human occupied space? If you're a few PSI short of external > pressure you're not going to get out. > Of course I'm concerned that scuttle valves can have problems as well, if something gets sucked in the valve and clogs it. Some sort of intake guard around the valve might help prevent it from clogging, but what if it's burried in silt? > > I like the idea of two scuttle valves (hey flooding the boat twice as fast isn't going to be a bad thing), and also having the H.P. air to help pressurize the cabin. But that's just me. > > I"m currious about your sub design, once you've pressurized the > cabin to external pressure, will you be leave via top facing hatch or a bottom facing hatch? > I'm wondering what type of issues will rise when opening the top hatch, for example, water > will come in and air will leave, will you leave in the bubble of air? or will it 'burp' out > some air leaving the hatch hard to open again? > > I think avoiding anything that could snag your sub is also key to > staying alive, but they are so many unknowns out there, and a lot of other people in ocean who > may not be acting in the safest (for you) way (who probably don't know you just under > them.... > > ANyway, pressurizing the cabin at depth with air takes a lot of (or > at least a fare amount) of air, pressurizing the cabin at depth with water takes a fare > amount of water. Water is free, air you must bring with you (if you run out of water when > flooding your sub, it's not a big deal ;-). > > Ian. > > -----Original Message----- > From: Fly Deep <flydeep4u@yahoo.com> > Sent: Mar 10, 2004 3:24 AM > To: personal_submersibles@psubs.org > Subject: Re: Fw: Re: [PSUBS-MAILIST] Escape Hatch Realities > > > Scuttle valves: It is a generally accepted rule of thumb that most > submarines will have high pressure air for the ballast system. There is no > need for a Scuttle Valve. All that is needed is a valve that can be opened > from the inside that will let in high pressure air into the pressure vessel till > it's equal with the outside. Then you will be able to open the hatch, I do have lots > of experience in submarines and it is not a normal procedure. It is > much better to make a good dive plan and we in submarines do not just get > tossed into the water and drive around all willy nilly across the > ocean floor. > This action would be a death trip waiting to happen. Next, the > life support > > system should be designed for a minimum of 72 hours for each person. > > > But in truth, if you get stuck on some thing you will probably die > from > > hypothermia before your life support is depleted. > > Also, it should be considered impossible to escape from a submarine > at > > any depth deeper than 200 feet. As the pressure is increased in > side the > > sub so that it�s possible to open the hatch you will become over > come by > > Nitrogen Narcoses. So at that point you�ll be having a bad day but > you may > > not care. These are the facts, don�t get hung up on any thing > down there. > > It will probably be the last hang up you�ll ever have. > > DJB > > > > --------------------------------- > Do you Yahoo!? > Yahoo! Search - Find what you�re looking for faster. > > |