Battery AMTB - Cortez (1943-1946) - Battery AMTB - Cortez was a World War II, rapid fire, 90mm gun battery on Coronado Beach Military Reservation, San Diego County, California. Battery construction started 29 Jun 1943, was completed 26 Aug 1943 and transferred to the Coast Artillery for use 14 Dec 1943. Deactivated in 1946.
The AMTB battery at Coronado Beach Military Reservation consisted of two 90mm guns mounted on 90mm M3 fixed gun mounts and two 90mm guns mounted on 90mm M1A1 mobile gun mounts. Concrete pads were provided for both fixed guns and wooden gun platforms were provided for the mobile guns. The mobile guns were not normally emplaced. Two earth covered concrete magazines provided protection for the ammunition. Electricity was provided by commercial power and by M-7 portable generators as a backup.
The battery had a dual mission of defense against fast enemy motor torpedo boats and enemy aircraft. The effective range of the guns was about 8,000 yards or 4.5 miles. Each weapon required a crew of 15, 9 men in the gun squad and 6 men in the ammunition squad.
From FM 4-91:
"This weapon consists of the 90-mm gun M1 and top carriage M1A1 on the 90-mm gun mount M3. The mount M3 is of the turret type, the shielding being constructed of boiler plates. This boiler plate shield provide fragmentation protection only. No shielding is provided at the rear due to the requirements for service of the piece. A sighting port in the shielding in front permits sighting in direction by the gun pointer."
References:
FM 4-91 - 90-MM Gun, Fixed Mount Service of the Piece
FM 4-126 - Antiaircraft Artillery, Service of the Piece, 90-mm Antiaircraft Gun
TM 9-373 - 90-mm Gun M1 and 90-mm Gun Mount T3 (M3)
Source: 1. RCW Form 1, 12 Apr 1944 2. CDSG 3. Berhow, Mark A. ed, American Seacoast Defenses: A Reference Guide, 2nd Edition, CDSG Press, McLean, VA, 2004, ISBN 0-9748167-0-1, pages 80-81, 217. 4. Report of Rounds Fired from Seacoast Artillery Guns, HD Commander, 17 Jan 1946, NARA RG165, E257 Box 68 - Bolling Smith.
