Jon,
Your right of course and I see I forgot to mention that the designs I worked up were made rather quickly to show a basic concept. I didn't scale, size, or space the steel for a working model. I can see what your seeing. Those pics if taken as is, would be over kill if you had a good thickness of outer hull over them. Of course allot of people here love there over kill. When your life is on the line as well as you passangers, a little over kill will make you sleep better. However at some point you have to say thats enough. Those models where in a 8' OD size with most of the steal being one inch thick to make it quick and painless. I'm not advocating using a thinner outer hull and as you seem to say there should be some sort of balance.
Or course adding horizontal ring supports would add some free board weight as well that would have to be dealt with in a little larger ballast tank as well as a little more weight in the keel to get the some stability you would get in a lighter freeboard design. Right now I'm partial to what I call design two, using the I-beam rolled to fit ones needs like in the Euronaut but with some horizontal supports. I think it's one of the quicker ways to go, considering.
I'm also not necessarily advocating one build there support ring structure then add the outer hull but it has been done once or twice before. Doing more of your welding in the open is a blessing if you can get away with it. Here's a pic you might find interesting.
http://img301.imageshack.us/img301/2553/constructionoftheubootzk3.jpg
Brent Hartwig
From: "Jon Wallace" <jon@psubs.org>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: RE: [PSUBS-MAILIST] Horizontal Pressure Hull Weldment Supports?
Date: Mon, 8 Jan 2007 00:50:42 -0500
Brent,I suspect there is no argument that could be made to suggest adding the horizontal frame members would be detrimental. The consideration to be made however is whether the work involved in constructing/installing such additional members are necessary (or justified) to acheive satisfactory safety margins for a given hull thickness and dimensions/span of circular support bands required to reach a particular maximum depth. I imagine it would be at least theoretically possible for example, to build a frame with circular/horizontal members so close together that you could reach 300 feet in a sub using 14 guage sheet metal as the hull material. Would that be more cost effective than using a 1/4" hull with circular supports every 12 inches? Probably not.Jon
