Battery Zeilin had two 7-inch Navy guns. The battery was named in honor of Lieutenant Jacob Zeilin who became Commandant of the Marine Corps.
Soon after December 7, the Marines turned both Batteries Gillespie and Zeilin over to the Army and their soldiers manned them on a twenty-four hour basis.
Colonel P. H. Ottosen kept the guns until Battery Woodward was completed in August 1944.