Re: [PSUBS-MAILIST] Perry lockout

Hello Frank,

I would venture to guess that the Simon Lakes Argonaut I was the first real submarine to have a diver lockout chamber where by you can open a bottom hatch and jump in. The link to a picture of the Argonaut I shows a downward opening hatch for the DLO.

http://www.tamu.edu/upress/BOOKS/1999/bigpoluw.htm

Even the Pitch Pine Submarine as the wooden prototype Argonaut Jr. was called. had a bottom diving hatch. Here is a page from Simon Lakes book call "The Submarine History of Simon Lake" I would guess that the Argonaut Jr was a ambient sub when the divers hatch was open as well as the rest of the time since the shape and material are not that conducive to 1 ATM operations.

http://www.amazon.com/gp/reader/0890968942/ref=sib_dp_pop_fc/103-9833771-7482211?ie=UTF8&p=S001#reader-link

The Kraka has this same basic set up in regards to the bottom hatch opening down and into the water, with a short rope to pull the hatch closed enough so it can be latched. Peter must of tested and planned for all his internal systems to be ok with the extra internal pressure it would take to pressurize the interior of Kraka so the bottom hatch could be opened and the water stay out of the sub. It's far easier to have the sub be ok with internal pressure on hatches, view ports, and the like if you only do it at depth. That way the sub is acting as a ambient sub while the divers bottom hatch is opened. Then you have to bleed off the extra pressure as you assend to the surface, either by leaving the bottom hatch open or valves and let the sub interior act as if it was a soft ballast tank, or use high volume pop off valves or use a high pressure air pump to return the interior of the sub to 1 ATM at depth.

http://www.vulcaniasubmarine.com/KRAKA.htm

The Euronaut on the other hand has a rotating hatch head that engages with what looks like eight dogs, and opens into the DLO. That's the only hatch in that bottom trunk unless he has another one below that opening down and into the water that I don't see, but I don't think there is a second hatch, so the seal on the rotating hatch in the floor would need the be tight and the eight dogs be able to with stand allot of pressure. Here is the picture of this hatch.

http://img411.imageshack.us/img411/13/0806588x425hu9.jpg

I've seen a stress analysis Carsten did on that hatch and so I'm sure he's worked it all out. Perhaps he will comment on this. Here is the link showing the stress analysis of the divers bottom hatch translated into English.

http://translate.google.com/translate?hl=en&sl=de&u=http://www.euronaut.org/&sa=X&oi=translate&resnum=1&ct=result&prev=/search%3Fq%3Deuronaut%2Bsubmarine%26hl%3Den%26rls%3Dcom.microsoft:en-US

Amateurs built the Ark.
Professionals built the Titanic.

Regards Brent

From: ShellyDalg@aol.com
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Perry lockout
Date: Sat, 27 Jan 2007 19:56:59 EST

Hello Brent. I've been following your thread and it sounds pretty interesting.

With a diver lockout hatch, could a guy pressurize the chamber, open the hatch, and reach out and grab stuff off the bottom? The hatch would probably need to open inward, and be VERY strong, but you may be able to get an old ship's bell, or some other memento of your dive.

Might be fun!.....Frank D.