20MM Gun Mount

20MM Gun Mount. U.S.S. North Carolina. This is a Swiss Oerlikon 20mm anti-aircraft gun. It was used to defend the Ship against close range air attacks. It replaced the older, less effective .50 caliber machine guns. In December 1941, forty 20mm guns were installed and more were added over the war years. There were single and twin 20mm mounts. They were known as the "door knocker" because of their limited range and short engagement time. , , A crew of four men operated each air-cooled gun: , . Gunner, strapped against shoulder rests, trained, elevated and manually fired the gun , . Talker/Spotter observed gunfire, watched for targets, and set the range on a Mark 14 gun sight (when in use) , . Trunnion operator raised and lowered the mechanical pedestal (trunnion) , . Loader placed the 60-round magazines on the gun.The loader removed the ammunition from the ready service lockers (steel boxes) located behind the guns. The 60-round magazines were stored in three clipping rooms, each manned by four men during general quarters. , , Crew Memories , "Plane came in over #1 turret, port to starboard Opened fire on plane as it went away from ship. Went about 2000 yards, turned around and came in for the ship. Opened fire at 1000 yards. Plane was hit and crashed into water." , Arthur Wiliam Hirt, Seamen 1/C , , "One black plane with a long fuselage and wheels came over the ship. My trunnion operator called my attention to it. I trained my gun at it, gave it plenty of lead and opened fire. The plane went for about 2000 yards and burst into flames and crashed." , Roy Arthur Jackson, Gunner’s Mate 3/C , (caption) , Below: Mechanical pedestal with ring sight. (The Battleship only displays the fixed pedestal mounts.)