Early in WWII the USN used our submarines for messenger and other mundane chores. Then the desk idiots were replaced by war fighters. Unrestricted submarine warfare became policy. We finally got torpedo technology that worked and the Japanese paid a big price. We also paid a price. Our lost boats dot the map in the seas around Japan.
Up to late in WW2 submarines were used for “mundane chores”, such as transporting agents and refugees, resupplying guerrilas, rescuing airmen, fleet scouting, scouting beaches, etc and etc. By late 1944 Japanese marus had become scarce and there were plenty of spare US submarines.
“We also paid a price. Our lost boats dot the map in the seas around Japan.”
The USN skimped on testing the early torpedoes, which failed more often than they succeeded. Our WWI torpedoes were much better!
This is one reason why I support funding our military at every opportunity. By being cheap, the Allies and the US Navy lost thousands of lives.