Armament of The Iowa Class Battleship - Secondary Battery

Secondary Battery

The secondary battery was a dual-purpose weapon system; it was designed to defend the ship from either surface or airborne threats. The original secondary battery consisted of 10 Mark 28, Mod 2 twin gun mounts, and four Mark 37 Gun Fire Control Systems. At first, this battery's effectiveness against aircraft diminished as planes became faster, but this changed toward the end of World War II through a combination of an upgrade to the Mk37 System and the development of the VT (Variable Time) proximity fuze. In preparation for the reactivations in the 1960s and 1980s, the battery was updated to the latest gun and fire control system modifications. In the 1968 upgrade to the USS New Jersey for service off Vietnam, three Mark 56 Gun Fire Control Systems were installed, two on either side just forward of the aft stack, and one between the aft mast and the aft Mk 38 Director tower. This increased New Jersey's anti-aircraft capability, because the Mk 56 system could track and shoot at faster planes. In the 1980s modernization, the Mk 56 GFCSs and four mounts were removed to make room for missiles, leaving the Secondary battery with four Mk 37 GFCSs and six twin mounts on all the Iowa class. By the time of the Gulf War the secondary battery was largely relegated to shore bombardment and littoral defense. Since each battleship carried a small detachment of Marines aboard, the Marines would man one of the 5-inch gun mounts.