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Greetings Dan, I did have a standard snorkel on my K boat. I have been planning to remove it and weld in the hole, since I plan to install a equalizing valve in the hatch. The equalizing valve is large so I can let out all the air in the sub for wet exit training, faster then you will need to put out when starting to breath on the SCUBA escape gear. Perhaps one will need to hold there breath for a bit so the air can bleed out of the said valve almost completely before opening the hatch while submerged. I didn't expect to need a snorkel, since I'll plan to install a O2 system, and two small CO2 scrubbing units. Plus since I'm adding a little over a foot to the height of the conning tower with a acrylic cylinder and I have a inflatable pontoon system planned. I can open the hatch in much rougher sea states for fresh air if need be, much more then I would of been able to had I kept the standard K-250 configuration. I still do not see why a large over pressure valve like is installed on the KSS, couldn't be mounted in the floor of a sub to bleed off extra pressure and be able to completely drain the interior of a sub of water with how flush it is to the bottom. It would act a bit like a open bottom ambient sub. It just wouldn't let water or water pressure in as just a simple hole in the bottom of an ambient would. I had not thought of how the temperature change while submerged would change the internal pressure. Very interesting. With my adding of 1.5" of syntactic foam to the interior of the main pressure hull, and 3/4" of syntactic foam to the interior of the steel portion of the conning tower, plus then coating all that with 3/16" of a Rhino Linner type coating, I should have much more insulating value then my sub once had. Regards, Szybowski From: Jumachine@comcast.net To: personal_submersibles@psubs.org Subject: Re: [PSUBS-MAILIST] Over Pressure Valve Options Date: Thu, 25 Jun 2009 07:32:15 -0400 Brent,
Does your sub have the snorkel on it? Most K subs built by Kittredge did.
When I surface I open the valve to the snorkel and equalize the pressure. It's almost always negative in the sub because of the temperature difference of the air I left the surface with and the internal temp of what I'm returning with. When I dive in New York States Finger lakes, the water temp isn't much over forty degrees all year around. At the end of a summer time dive in there, I vent to equalize and have to swallow to clear my ears because they pop so much when I surface and vent. It's difficult to open the hatch if I don't first vent.
If you were positive pressurized from a problem, your snorkel should release it. The barometer is a good idea but you shouldn't need any extra piping if you have the snorkel.
Dan H.
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