Mass production of submarines
 

The Salmon class of "fleet" submarines of 16 boats, commissioned as Navy warships 1938–1939, were the climax of decades of development by submarine veterans. They were based at Manila in the Philippines when war started.

The Tambor class of six improved on the Salmons, and were commissioned in 1940–1941. The lead boat, Tambor, tethered underwater was depth charged to test her hull and fixtures. The Gato class of 12 in 1941–1942 were Tambors. Some of these were based out of Pearl Harbor on December 7, 1941.

With war the Tambor-Gato design was frozen. The Navy ordered this design into mass production.

hull under construction

This is part of the pressure hull of the Wahoo under construction at the Mare Island shipyard in 1941. Many parts were partially assembled as above before becoming part of the submarine on the building ways before launch.

After being christened with ceremony and launched, heavy components like the Diesels and batteries were installed, so the entire boat and the sea supported the weight.

During the war early in construction members of the crew reported, and worked alongside shipyard workers watching the installation of the miles of wires and tubes and other parts of the boat, so they could make repairs when deep in enemy waters.

When completed, they were commissioned, tested equipment, then often worked with new destroyers and escorts to perfect crew skills before traveling to Pearl for final training and evaluations for their first war patrol.

When the Redfish returned to the shipyard where she was built after a brutal depth charging that dished in and cracked the pressure hull, workers walked through the submarine. Crewman reported workers going to where they had worked, pointing to the hull and saying, "My weld held!"