In the fall of 1942, the Army decided to install 90-mm anti-motor torpedo boat (AMTB) batteries in the harbor defenses. Each battery consisted of two fixed and two mobile guns. The mobile guns were kept in storage until an emergency occurred. Built in 1943, this battery was operational from 1944 until 1946.
The mission of these batteries was to attack enemy motor torpedo boats, to defend against enemy landings, to assist against enemy air attacks and to attack enemy submarines within range.
