I'm planning on another K-sub, but thinking about a box keel like the Nektons and Delta had, rather than pods. Has anyone got an idea about how to figure structure on something like that? The Nekton's box was 9/16" wall, flat side and bottom, and reinforced with flat plates running athwartships on 18" centers (more or less). The hulls were the same thickness and the same material (A516 Grade 70).
I'm wondering if there would be any penalty to building a 1/2" thick box with 1/4" dividers matched to the ring stiffeners in the hull (ie., 12" centers). The box would be a foot square in cross section, and if all seems well, would be welded through a slot in the hull and covered inside with a reinforced aluminum deck plate gasketed and vented for charging. If the pressure hull is six feet long in the cylinder, that would give me room for a grunch of 85 amp deep cycle batteries (more than called for) and still not kill my payload.
Anyone not familiar with K-subs might think all this sounds pretty heavy. Have a look at the lead load in Dan's boat, if you think we don't have it to spare.
Vance