Peacetime ships are also expected to last (Googling) 36 years in good condition. I'm sure it was a concern in WWII, and that they took all steps they could to

Peacetime ships are also expected to last (Googling) 36 years in good condition. I'm sure it was a concern in WWII, and that they took all steps they could to preserve their vessels, but I'm also guessing that as long as they weren't rusting so fast as to become junk in three or five years, they were much more worried about surviving combat than rust.