A World War II class least desirable to serve in

In World War II, which ship class would you least want to be assigned to?

For the Royal Navy, the Grampus-class submarines are the choice because of their exceptionally poor survival record; some American minesweepers also rank badly.

The Grampus-class minelaying submarines are the least desirable Royal Navy assignment in this answer. HMS Rorqual was the only member to survive the war in British service, while HMS Seal was captured and entered German hands. That record makes the choice about operational survival instead of comfort or appearance. Some American minesweepers would be equally unattractive assignments for the same risk-based reason.