22 Intelligent Whale Hand Crank

The hand crank handle is about 1.75' wide. There are two handles and one crewman would sit on either side allowing 4 men to crank at one time. With an expected crew of 13 I'm guessing that they were planning to crank in shifts.

One or both of the square headed shafts (one is in the left side of the photo) are probably the hand cranked windlass for the raising and lowering of the spherical anchor at that end of the submarine.