[RightWhale]

The pressure hull must be flexible but must not bend. Did you ever do the experiment where you tie a rope tight to some equipment across the aisle from one side of the sub to the other side while on the surface and then dive to some depth? The rope will hang loose at depth as the pressure hull is compressed in diameter, which comes as a surprise to some the first time they see it happen.

[blam]

"Did you ever do the experiment where you tie a rope tight to some equipment across the aisle from one side of the sub to the other side while on the surface and then dive to some depth? "

No, I never tried that although, I understand it.

[Bear_Slayer]

In reverse, would a rope tied at lowr depths snap when the sub surfaces?