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Re: [PSUBS-MAILIST] Vacuum test

Frank, Brent, all,
The amount of vacuum is less important than the MEASURABLE amount of vacuum. There are lots and lots of places to leak test, but if you put a vacuum on the boat and it holds, then you don't have to hunt for them, because their aren't any. And FYI, the Deep Worker operators pull a minor vacuum before EVERY dive (after the pilot buttons up) to set the o-rings and verify watertight integrity. Not a bad idea to emulate for subs that don't get to the water very often.
Vance

-----Original Message-----
From: Brent Hartwig <brenthartwig@hotmail.com>
To: PSUBSorg <personal_submersibles@psubs.org>
Sent: Mon, 1 Jun 2009 10:27 pm
Subject: RE: [PSUBS-MAILIST] Vacuum test


Howdy Frank,

I don't see a vacuum test as being that hard, and if it saves you a trip to the water then it might save even more time over all, not to mention the cost of a crane in some cases such as Alicia and the British Navy watching. Also in some subs they have components and/or operators that are allergic to water. ;}

 I just consider it one of a progression of test in getting the sub ready for manned ops.  I'm working on a configuration for a timer and back up timer that control pneumatic valves that will put air into the MBT's and another timer set at a longer time period to turn on a high pressure pump to drain my bladder VBT, for unmanned deep water testing so I don't have to pull it up manually or with a winch.  Although now I have a 32 ft tender motor yacht with a anchor winch available to me for this test to I have a good back up if the sub doesn't become fully flooded. 

Also this timer system can be used for a type of dead man switch for normal manned sub ops, so that if the pilot goes unconscious  the sub will surface on it's own.

I'll post in regards to galvanizing in a moment.

Regards,
Szybowski




From: ShellyDalg@aol.com
Date: Mon, 1 Jun 2009 21:45:21 -0400
Subject: Re: [PSUBS-MAILIST] Vacum test
To: personal_submersibles@psubs.org

A vacuum test sounds like a way to check for a pin hole leak, but seems like a lot of work. A pin hole at 250 feet will squirt some water maybe, or more likely drip some, but if you welded the fittings, hull, tower, etc. your self you should know if it's screwed up. I'm not sure a shop vac test for leaks is all that useful.
Deep water testing un-manned via cable and/or remote control is still going to be required, and it's quite possible a pin hole leaking at depth wouldn't leak at 2 feet or with a shop vac. Nice little exercise though if you've got time on your hands.
Brent: are you hot dipping the entire hull ? I love that idea, but it sounds expensive. Got any more info on this? Frank D.
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