Jay,
You make a very good point, about using syntactic foam as much as possible in a way you can work on, or reconfigure the sub in the future. I've had that in mind for some time now. Some designs can be done in such a way the the syntactic foam is apart of the strength of a pressure hull, like the beautiful R300. In that case I would make sure the metal is carefully treated before it is encased in foam and forget about trying to do a major reconfiguration later.
With regards to my design of filling the spaces between the ribbing of a K-250 internally, to insulate, sound deadening, and some extra strength that could be needed in a emergency like a collision with something or forced deeper then 250'. I could attach the foam solid to the hull for maximum strength, or wax and then spray a mold releasing agent on the steel hull surfaces, and then cast the foam. This way the foam can be removed much more easily.
I still don't know how much difference there is in the expansion and contraction of the foam to a metal hull, wether the foam completely covers the inside, the outside, or both, as well as if it's just on part of the hull, like on the Idabel? Will the foam want to pop loose, or will they move together? I'm aware that it would also depend on the hull size and thickness, as well at the foam type and thickness. Doc is using a urethane binder in the new two seater Bionic dolphin. The urethane will flex allot more then a most resins used to cast syntactic composites and so it will not have as high of depth rating as most other types.
Regards,
Brent
From: "Jay K. Jeffries" <bottomgun@mindspring.com>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: RE: [PSUBS-MAILIST] MIG Welding a Sub
Date: Tue, 31 Jul 2007 20:31:05 -0400
Sorry for the late reply. You need to be careful with syntactic foam. The old Asherah (STAR I) had its main battery foamed in with syntactic foam which resulted in a major stumbling block for refurbishment as it was very difficult to remove. This submersible and a custom built saucer submersible were stored in a warehouse next to where we docked in Boston. Took forever to rebuild Asherah due to the syntactic foam and the saucer had major stability and power issues.
R/Jay
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas