Battery AMTB 968

From FortWiki
Jump to: navigation, search

Battery AMTB 968 (1943-1946) - Battery AMTB 968 was a reinforced concrete World War II AMTB rapid fire 90mm gun battery on Jewell Island Military Reservation, Jewell Island, Cumberland County, Maine. Battery construction started in 1943, was completed in 1943 and transferred to the Coast Artillery for use in 1943. Deactivated in 1946.

World War II

Part of the Harbor Defense of Portland, Maine. There were two AMTB batteries on Jewell Island Military Reservation. Battery AMTB 967 was on the southeast end of the island. Battery AMTB 968 was located on the northeast end of the island.

Each AMTB battery at Jewell Island 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 often wooden gun platforms were provided for the mobile guns. Two earth covered concrete magazines provided protection for the ammunition. Electric power was provided by M-7 portable generators.

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.

AMTB Front View
AMTB Interior View
AMTB Side View
AMTB Back View

The above photos were taken at Fort Monroe, Battery Parrott

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."


  • 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)

Current Status

Private property, no period gun or mounts in place but both gun blocks are visible.

Location: Jewell Island, Cumberland County, Maine

Maps & Images

Lat: 43.683209 Long: -70.089206

  • Multi Maps from ACME
  • Maps from Bing
  • Maps from Google
  • Elevation: .....'


  • U.S. Army Corps of Engineers, FUDS Archives Search Report, Findings, Jewell's Island Military Reservation , Project No. D01ME012602, September 1995. Large PDF Download
  • U.S.Army, Supplement to the Harbor Defense Project of Portland, Maine, (HDPB-AN-45), 11 Apr 1945, CDSG


Visited: No

Personal tools