16th Coast Artillery ( United States ) The 16th Coast Artillery Regiment was a Coast Artillery regiment in the United States Army , manning the harbor defenses of Honolulu , Pearl Harbor and the perimeter of Oahu , Hawaii during World War II . The Regiment manned a large number of gun batteries at locations all over Oahu . The forts where they were assigned date to the 1890s , and had were in caretaker status for more than 30 years . On the morning of 7 December 1941 , it was the soldiers of the 16th Coast Artillery who manned the anti - aircraft guns , bringing down six of the Japanese attack aircraft . Forts and Batteries manned by the 16th Coast Artillery . Fort Ruger . Fort Ruger was located in and around Diamond Head . The interior of the volcanic cone was accessible through two tunnels large enough for trucks . The administrative buildings were on the north side of the cone . The batteries included mortars placed when the fort was created , dating to 1910 . The eight inch battery was built six years prior to World War II . Battery Ruger , like all of the 155mm batteries were temporary emplacements using four " Panama mount s " , a circular track surrounding a center pivot where a 155mm cannon was mounted . Battery Granger Adams was a typical coast defense emplacement , with the structure buried to provide protection below a parapet . Fort DeRussy . Fort DeRussy was located adjacent to Honolulu , on a portion of Waikiki Beach . The large caliber guns are mounted to disappearing carriages that use the recoil to lower the gun from the parapet to the loading platform . The allows the reloading crew a work area protected from shells fired by off - shore ships . The Anti Motor Torpedo Boat ( ATMB ) battery protected the close - in area around the fort from attack by high - speed motor torpedo boat s . Fort Armstrong . Fort Armstrong was located at Kaakaukukui Reef , located at the east side of the entrance to Pearl Harbor . Fort Hase . In 1918 , President Woodrow Wilson designated of land on Mokapu Peninsula , naming it Kuwaahoe Military Reservation . In 1939 , the Navy constructed a small seaplane base there , designated as Naval Air Station Kaneohe Bay . The Naval Air Station ' s role was expanded to include the administration of the Kaneohe Bay Naval Defense Sea Area . A part of the 16th coast artillery moved onto the reservation in 1941 . In 1942 the portion of the reservation that was occupied by the Coast Artillery was designated Fort Hase . Lineage . Constituted 27 February 1924 as 16th Artillery ( HD ) Coast Artillery , and organized 1 July 1924 at Fort Armstrong , ( Hawaii ) from the following Companies - 104th , 90th , 99th , 105th , 111th , 159th , and 186th . 1st and 2nd Battalions HHB , and Battery B were activated 6 August 1942 ( Battery D was inactivated through Detachments ) The Regiment was broken up 29 May 1944 and personnel were transferred to 15th Coast Artillery ( United States ) . The Regiment was then transferred to HD Kaneohe Bay and reactivated with personnel from 41st Coast Artillery A Gold color metal and enamel device 1 3 / 16 inches ( 3 . 02 cm ) in height overall consisting of a shield blazoned : Or two spears in saltire Gules , within a bordure embattled barry of eight Argent , of the second and Azure , repeated . The shield is essentially Hawaiian . The crossed spears are taken from Hawaiian history , they were formerly placed at the King ’ s tent , and are shown conventionally in the Hawaiian arms by a saltire cross placed on an inescutcheon . The distinctive unit insignia was originally approved for the Coast Defense of Honolulu on 25 July 1922 . It was amended to change the description on 6 December 1923 . The insignia was redesignated for the 16th Coast Artillery Regiment on 27 February 1929 . It was redesignated for the 16th Antiaircraft Artillery Gun Battalion on 11 September 1952 . Or two spears in saltire Gules , within a bordure embattled barry of eight Argent , of the second and Azure , repeated . On a wreath of the colors Or and Gules a representation of Diamond Head Gules . Motto KAPU ( Keep Out ) . The shield is essentially Hawaiian . The crossed spears are taken from Hawaiian history , they were formerly placed at the King ’ s tent , and are shown conventionally in the Hawaiian arms by a saltire cross placed on an inescutcheon . The motto , probably the best known Hawaiian word , is used extensively as a sign against trespassers . The batteries at Diamond Head constitute the principal element of these defenses . Coat of arms . Background . The coat of arms was originally approved for the Coast Defense of Honolulu on 27 January 1922 . It was redesignated for the 16th Coast Artillery Regiment on 27 February 1929 . The insignia was redesignated for the 16th Antiaircraft Artillery Gun Battalion on 11 September 1952 . Campaign streamers . World War II Decorations . unknown