Wiljan:

The Draeger device was similar to the U.S. Navy's Momsen Lung. The U.S. fleet boats had an escape trunk in the forward torpedo room and in the after torpedo room, a skirt was attached to the bottom of the escape hatch trunk, and the torpedo room was flooded to equalize pressure same as the U-boats.

Two additional features for escape and salvage were:

1. Each ecsape hatch deck area had a machined surface with four padeyes welded
at 90 degrees, to accept a McGann escape (bell) chamber, to permit escape of
trapped men in a submarine.

2. Each compartment on the submarine was fitted with upper and lower salvage piping, which permitted the compartment to be blown dry form the surface with
the use of deep-sea divers.

Later,

ROBERT M.