Re: [PSUBS-MAILIST] MBT Vents

You already know what I think of the in and out vent so I won't belabor the point. That said, I'd really like to see the lower hull stop valve in you sketch on the welded nipple with the air supply inboard. Also, you might consider using Swagelok fittings and SS tubing, rather than the welded pipe. It will be more resistant to corrosion and will let you form the tubing to follow the hull shape, which will clean up the installation and let you disassemble more easily as required.

-----Original Message-----
From: ShellyDalg@aol.com
To: personal_submersibles@psubs.org
Sent: Tue, Mar 9, 2010 12:37 pm
Subject: Re: [PSUBS-MAILIST] MBT Vents

.........."They're not stainless, and they're ported way too
small, so it takes several minutes to vent the MBTs. "...........

Hi Alec. I've always thought Snoopy was one of the best psubs I've seen.

On your vents,what size is used now ? How long does it take to vent the tank completely ?

I am using 3/4 inch schedule 80 316L nipples for thru-hulls because they fit 1" valves. The interior piping is schedule 40 X 1". Bigger is better but a larger thru-hull means bigger valves and piping, and I'm curious how long it will take to flood. Here's a little sketch.

The holes in the bottom of the ballast tanks are 2 each at 2-1/2" diameter.

Frank D.