The original release of Silent Hunter 4 was based on the wildly successful Silent Hunter 3 and large portions of the older game were just ported over to the new game while swapping sides and updating the graphics.

Silent Hunter 4: Wolves of the Pacific is a submarine simulation set in the World War Two era developed by Ubisoft and was released in 2007. Sub Commander shortly after December 7th, 1941, 'The day that will live in Infamy.' There are also mods available that allow the player to: start a U.S based campaign prior to December 7th,or even play as the commander of a surface ship. Silent Hunter IV takes players behind the periscope of a German Type IX U-boat to take on the Allied Forces in battles in the Pacific Or the player can optionally switch sides and play as a U.S.

3.2 Historically Inspired IJN, USN, Axis, Allied & Merchant Vessels.3.1 Historically Inspired Player Vessels.2.2 Known Bugs, Issues,(and possible fixes).