 This need was initially met by transferring 4"/50 caliber guns from S-class submarines as they were shifted from combat to training roles beginning in late 1942.Later, the 5"/25 caliber gun, initially removed from battleships sunk or damaged in the attack on Pearl Harbor and later manufactured in a submarine version, became standard.When multiple hits from Oerlikon 20 mm cannon and Bofors 40 mm guns were unable to prevent kamikaze strikes during the final year of the second world war; the 3"/50 was adopted as a replacement for these weapons.