Thanks Jay, That makes sense to me, since the air is displacing exactly that much water, which is being kept done below the waters surface by the weight in the sub to become neutrally buoyant. So since the air in the cabin is basically very close to the surrounding water pressure, difference being the constantly added air for breathing and the slight difference in water pressure at the bottom of the sub from the top. Then we add the buoyant force on the upper surfaces. Which I was thinking would be applied to the sides as well, on a gradient scale gaining more pressure as you go towards the ceiling. Which if correct would mean it would be harder to calculate. But to be safe you could make the ceiling able to easily with stand all the buoyant pressure to a FOS of 2 or more, plus make the side equally strong. So this would seam to mean to me, that the ceiling will have a good bit higher psi being applied to it, over the lower pressure water on the other side of the ceiling. I had been toying with the idea of making one or more of the really amazing FRP kit car kits out there, into an ambient sub, with a view to die for, but for go the dying part. So I didn't want my windshield t pop out or brake out. I was thinking about using the commercially available automotive wind shields for the sub, and adding stronger exterior flanges to secure it. The other option was to use the glass wind screen, for a blow mold, or drape mold to form a new wind shield out of acrylic. Any thoughts. Your resident bubble boy dreamer ;)' Regards, Szybowski From: bottomgun@mindspring.com To: personal_submersibles@psubs.org Subject: RE: [PSUBS-MAILIST] Upward Buoyant Pressures on Ambient Interior Surfaces Date: Thu, 4 Sep 2008 18:58:20 -0400 Brent, Two things need to be sorted out in this mental exercise. How many cubic feet of air? Convert this into the weight of the equivalent volume of water…this is the force pushing up. Now have many square inches of surface (upward side) is that air applied to? Divide the force (equivalent pounds of water) by this surface area and you have the PSI sensed by the interior overhead. As you descend, the bubble gets smaller is no air is added, buoyancy decreases, and the applied air pressure to the top surface decreases. Water force inside and out are the same for an ambient sub. R/Jay
Respectfully, Jay K. Jeffries Andros Is., Bahamas
Talk sense to a fool and he calls you foolish. - Euripides (484 BC - 406 BC)
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent Hartwig
Upward Buoyant Pressures on Ambient Interior Surfaces Your resident bubble dweller ;)'
To: personal_submersibles@psubs.org I think the correct answer is "almost" no difference.
Best of Luck
-----Original Message----- In ambient sub senses the same pressure inside or out so there is no difference having the gage inside or out. R/Jay
Respectfully, Jay K. Jeffries Andros Is., Bahamas
Talk sense to a fool and he calls you foolish. - Euripides (484 BC - 406 BC)
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of djackson99@aol.com
Hmmmm... Not the weight of the sub. It should indicate the depth of the vent where the air is released into the surrounding water and likely a little deeper since the constant flow of air may add a few psi to the ambient cabin. Air at the top of the cabin is at the same pressure as the air at the bottom of the cabin where it is vented to the surrounding water. So it does not matter where the gauge is inside the cabin.
-----Original Message----- In an ambient submarine, if one uses a dive watch type depth indicators to give an indication of how deep He is, does this display the actual depth or will it be off a little having the additional weight of the sub working on it? One of those HMMMM thoughts... Be the filmmaker you always wanted to beearn how to burn a DVD with Windows. Make your smash hit= |