[WildTurkey]

Thanks. I had made a couple of posts asking and looked for a diagram but couldn't find one.

[Robert A Cook PE]

Yeah: On WWII boats, the ballast tanks were all the length of the hull (pretty much) and wrapped around the pressure hull. A free-flooding open area (the fairwater) was under the flat (visible) deck for surface running and surface combat with guns..

Post Albacore hull, the original Permit and Thresher boats has the FWD MBT's wrapped around the pressure hull, the mid MBTs wrapped around the pressure hull, and the aft ones kind of stuck on and smoothed in.

On 688's, the fwd three MBT's are concentric around the very small 32" (?) pressure-tight access tunnel to the sonar sphere itself. Then comes the fwd elliptical bulkhead, then there are NO mbt's until the aft elliptical bulkhead, where MBT 4A/B and 5A/B are. So the pressure IS the outside surface for the entire middle of the ship, with only about 4-5 feet of MBT3A/B faired into the elliptical bulkhead.

Much of what you see squashed on the port side used to MBT's and torpedo tubes hatches and outer doors. AHP tanks (banana's) also.