RE: [PSUBS-MAILIST] K-350 Reinforcing Ribs

Subject: RE: [PSUBS-MAILIST] K-350 Reinforcing Ribs

From: "Daniel Lance" <lanceind@earthlink.net>

Date: Mon, 1 Oct 2007 19:49:45 -0400

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Reply-to: personal_submersibles@psubs.org

Sender: owner-personal_submersibles@psubs.org

Charles,

If you are considering building a K-350 from plans and expect to have the designed depth capability and durability then it is absolutely necessary that you use ASTM 516 Gr 70 steel. 516 Gr 70 is only available in plate so therefore one must fabricate the tee bar from strips sheared or water jet cut from plate. After welding it is common to have to machine the O.D. to acheive near perfect roundness ( within a 1/64th is probably close enough but get it as close as you can ). If you are going to water jet cut the strips ( roughly 111.50 inches long) don't fall prey to the idea of gaining a short cut by cutting segments of a circle and then welding them together to form the web part of the tee. This is ultimately a more labor intensive method ( ie. more welding and you still have to machine them).

If you are building a sub from your own design I would highly recommend that you use a PVQ ( Pressure Vessel Quality ) steel for the pressure hull. The level of quality of A36 mild steel today can be very poor due to the large amount of product imported from overseas where it is made with little or no quality control. I thought this thread had been pretty much beat to death earlier this year but at least this time it will be preserved in the archive under a proper title and possibily go another year before it is resurrected again.

All the best,

Daniel Lance

----- Original Message -----

From: Simone, Charles

To: personal_submersibles@psubs.org

Sent: 9/30/2007 11:42:52 AM

Subject: [PSUBS-MAILIST] K-350 Reinforcing Ribs

Hello Group,

I know this has been talked about on the list before, but I figured it would be ok to start the thread again.

The K-350 reinforcing rips are two pieces welded together to form a ?T? I have a machine shop that can roll these pieces out of ?T? stock leg out. I would assume it would have the same purpose as what the original design calls for. Does anyone have any feedback on this?

Also, for those who have built a hull, did you actually machine the OD true? Or just weld the gaps between the rings and the hull?

Thank you for your help.

Charles