While the submarine was primarily a torpedo platform, there were occasions when alternate weapons were necessary. Rapid submergence with the approach of an  enemy aircraft was the best defense against an aerial attack, but when a quick dive was unable to be made, anti-aircraft guns were needed. In addition, attacks against smaller enemy vessels such as sampans or barges was also generally carried out with a sub's deck guns. The largest weapon carried aboard a US submarine was the 5 inch 25 caliber (MK40) cannon. Housed on a moveable mount, submarines located these weapons abaft of the cigarette deck.

This weapon was as efficient in laying down a barrage of anti-aircraft fire as it was in delivering salvos during shore or vessel bombardments. Semi-automatic and rapid firing, it allowed the crew to fire an average of 10 to 15 rounds per minute. This cannon was capable of sending a 54 pound projectile 18,000 yards and possessed a maximum aerial range of six miles.

GUN CREW

Pointer
Trainer
Sight-setter
Gun Captain
Fuse-setter
Hot Shellman
Loaders