[PSUBS-MAILIST] Propane tanks, pressure rings

[ToolRoomTrustee@aol.com]

I recall seeing pictures of Italian WWII submarines that carried those "maile"
torpedo like diver carrying vehicles.  AIR the pressure tight containers had external ribs.  Using those on a personal sub would likely mean you'd need a fairing over them to avoid excessive water resistance but would be easier to apply if you weren't cutting the end of the propane tank off anyway.  One problem with external rings is that you'd likely have to weld it all the way around the rings to tank contact area
whereas inside the sub wouldn't welding just swerve to hold the rings in place.

FTM if you wanted internal rings, couldn't you just cut them in hemicircles to slip inside the hatch and then weld them back together as full circles when properly placed?

Larry Murray (who is just an armcahir sub builder)