 FAKE: During the credits, the view shifts between underwater and  "historical" scenes. In one underwater scene, one of this ships  port side gun houses is in view. The corresponding "historical" view  fades to one of the ships 5" mounts (2 guns/ mount). In the  underwater scene, there are clearly 3 openings for cannon in the gun  house. This means the mount in the underwater view is a 25mm gun  house.