In theory, yes. But you're now working on the reverse-idea of what an ambient-pressure sub is built for. Now you're trying to keep the built-up pressure inside the sub, and one of the main reasons for building an ambient in the first place is that you don't have to stress the hull for extreme pressure differentials.
If you're considering decompression in any type of sub, then you need to talk face-to-face with a certified SCUBA instructor.
NP
From: "Patrick" <pat_man_ta@hotmail.com>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: Re: [PSUBS-MAILIST] Ambient / 1ATM Q?
Date: Fri, 20 Jan 2006 14:32:59 -0500
Could one then, in theory, close the pressure release valve and decompress manually in the sub at the surface?----- Original Message -----From: Nomdae PlumeSent: Friday, January 20, 2006 2:05 PMSubject: Re: [PSUBS-MAILIST] Ambient / 1ATM Q?>I have a couple of questions.>Would this not place the interior of you sub at the same outside atmospheric pressure?Yes. The idea behind an ambient-pressure sub is that the inside-pressure is equal to the outside pressure. This allows you the option of building your sub with materials that won't have to take the stresses of keeping all that outside pressure out.
>Will this also place the same pressure on the human body in the sub?
Yes. Diving in an ambient-pressure sub places the same amout of pressure on the occupants as if they were swimming outside the sub at that depth.
>If this is true, in the event if an emergency rise to the surface, wouldn't this cause "the bends"?
Yes and No. You have to follow the same decompression rules as any SCUBA diver would. If you were to dive to 20 feet, then suddenly have to surface, your ears are going to hurt but you won't get the bends. This is why the typical depth limit for ambient-pressure subs is about 120 feet.
I believe that Bill Akins can give you a much more detailed explanation if you so require.
NP