Jay,
Thanks for the correction on units, I know better. As Jon
pointed out, a square tube will experience a greater pressure due to its larger
area. Don’t think you will find many submariners using square tubing though. J
R/Jay
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas
As scarce as the truth is, the supply has always been in excess of
the demand.
-Josh Billings
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of James Barlow
Sent: Tuesday, January 06, 2009 7:19 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Soft ballast venting valve
As the pressure
is already in PSI then the force (pounds) pushing your plug out of the 1/4"
leak is the 219 or 275 pounds not PSI. whatever the math is
(I didn't figure it out) but you have to apply that many pounds not psi.
Jay. (B)
|
Jon
Wallace <jon@psubs.org>
Sent by:
owner-personal_submersibles@psubs.org
2009-01-06
17:11
|
Please respond to
personal_submersibles@psubs.org
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To
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personal_submersibles@psubs.org
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cc
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Subject
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Re:
[PSUBS-MAILIST] Soft ballast venting valve
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Thanks for that Jay. The 125 pound figure didn't sound right to me
either and I calculated a pressure of 275.125 pounds for a square 1/4
tube, but was too lazy to look up the formula for a 1/4 round tube.
Jon
Jay K. Jeffries wrote:
>
> Some notes on this discussion:
>
> 1. I have had the opportunity to spend some time in a US Navy
> submarine damage control simulator as part of a team that took on a
> series of leaks. With a team, a lot more room than found in a PSUB
> (even a large one), proper damage control response resources, and cold
> water under pressure, we were hard pressed to stop a variety leaks
> that would be encountered aboard a submarine. It was very stressful
> but someplace in the back of your mind you knew that it wasn’t real,
> there was a hot shower waiting for you, and there would definitely be
> at least a cold beer at the end of the day. Aboard a typical PSUB,
> there has been little if any previous damage control training, there
> are few resources available to combat a leak, reserve buoyancy is at a
> premium, you probably don’t have someone to assist in combating the
> casualty, and it is VERY cramped.
>
> 2. The actual pressure behind a ¼” leak at 10,000 fsw:
> 1 fsw = 0.445 psi therefore 10,000 fsw equals 4450 psi.
> The area of a circle (A) equals π times the radius squared, where the
> radius in this case equals 0.125” resulting in an area of 0.0491 in.^2
> Therefore the pressure through our ¼” tube at 10,000 fsw equals (4450
> x 0.0491) ~219 psi.
>
> 3. A hatch that is leaking in shallow water may not stop leaking with
> an increase in depth as the inflow of water disrupts the seating
pressure.
>
> Later,
>
> Jay
>
> Respectfully,
>
> Jay K. Jeffries
>
> Andros Is., Bahamas
>
> */As scarce as the truth is, the supply has always been in excess of
> the demand./*
>
> -Josh Billings
>
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