BRP Diego Silang ( PF - 9 ) BRP " Diego Silang " ( PF - 9 ) was an " Andres Bonifacio " class frigate of the Philippine Navy in commission from 1976 to 1990 . She and her three sister ships were the largest Philippine Navy ships of their time . History . Construction and United States Navy service 1944 - 1946 . " Diego Silang " was built in the United States by Lake Washington Shipyard at Houghton , Washington , as the United States Navy " Barnegat " - class seaplane tender USS " Bering Strait " ( AVP - 34 ) . Commissioned in July 1944 , " Bering Strait " served in the Central Pacific during World War II and on occupation duty in Japan postwar . She was decommissioned in June 1946 and placed in reserve . United States Coast Guard service 1949 - 1971 . The U . S . Navy loaned " Bering Strait " to the United States Coast Guard , which commissioned her in 1949 as the " Casco " - class Coast Guard cutter USCGC " Bering Strait " ( WAVP - 382 ) . Reclassified as a high endurance cutter and redesignated WHEC - 382 in 1966 , she patrolled ocean stations in the Pacific Ocean , for nearly 22 years , reporting weather data and engaging in search - and - rescue and law - enforcement operations . During the Vietnam War , she served two tours off Vietnam , in 1967 - 1968 and in 1970 . Republic of Vietnam Navy service 1971 - 1975 . " Bering Strait " was transferred to South Vietnam in 1971 and was commissioned into the Republic of Vietnam Navy as the frigate RVNS " Tran Quang Khai " ( HQ - 02 ) . When South Vietnam collapsed at the end of the Vietnam War in April 1975 , " Tran Quang Khai " fled to Subic Bay in the Philippines , packed with South Vietnamese refugees . Acquisition by the Philippines . On 22 May 1975 and 23 May 1975 , a U . S . Coast Guard team inspected " Tran Quang Khai " and several other former " Casco " - class cutters which had been transferred to South Vietnam in 1971 and 1972 and , like " Tran Quang Khai " , fled to the Philippines in April 1975 . One of the inspectors noted : " These vessels brought in several hundred refugees and are generally rat - infested . They are in a filthy , deplorable condition . Below decks generally would compare with a garbage scow . " After " Tran Quang Khai " was cleaned , repaired , and made ready to return to service , the U . S . Navy transferred her to the Republic of the Philippines , with the formal transfer occurring on 5 April 1976 . Philippine Navy service 1977 - 1990 . The ship was acquired by the Philippine government on 5 April 1976 , and was commissioned as Philippine Navy frigate RPS " Diego Silang " ( PF - 9 ) . On June 1980 she was reclassified and renamed as BRP " Diego Silang " ( PF - 9 ) , and served the Philippine Navy until her decommissioning on June 1985 . She was again recommissioned afterwards as BRP " Diego Silang " ( PF - 14 ) and was finally decommissioned on April 1990 . Disposal . After finding her beyond economical repair , " Diego Silang " was discarded in July 1990 and probably scrapped . Some of her usable parts were made available for her sister ship BRP " Andres Bonifacio " ( PF - 7 ) . Technical details . There were changes made to the " Andres Bonifacio " class as compared to their original design during its service with the US Navy , US Coast Guard and the Republic of Vietnam Navy . The ships were passed to the Philippine Navy with fewer weapons on - board and old surface search radars , and these were addressed later on by the Philippine Navy through modernization programs , including the addition of a helicopter landing pad in 1979 . The single Mk . 12 5 " / 38 caliber gun ( 127 mm ) was " Diego Silang " s primary weapon . It was mounted in a Mark 30 Mod 0 enclosed base ring and had a range of up to yards ; the gun was a dual - purpose weapon , capable of anti - surface and anti - air warfare . She also carried two twin Mk . 1 Bofors 40mm anti - aircraft gun mount s , four Mk . 4 single 20 - millimeterOerlikon anti - aircraft gun mounts , four M2 Browning . 50 - caliber ( 12 . 7 - millimeter ) general purpose machine guns , and two 81mm mortars . A helicopter deck was added aft in 1979 by Hatch and Kirk , Inc . It could accommodate a MBB Bo 105 C helicopter used by the Philippine Navy for utility , scout , and maritime patrol purposes , although the ship had no capability to refuel or otherwise support visiting helicopters . Radar system installed include the Sperry SPS - 53 Surface Search & Navigation Radar replacing the previously installed AN / SPS - 23 , while retaining both the AN / SPS - 29D Air Search Radar and Mk . 26 Mod . 1 Fire Control Radar System . " Diego Silang " was powered by two Fairbanks - Morse 38D diesel engines with a combined power of around 6 , 200 brake horsepower ( 4 . 63 megawatts ) driving two propellers . The main engines could propel the 1 , 766 - ton - displacement ( standard load ) ship at a maximum speed of around . She had a maximum range of at an economical speed of . The Philippine Navy made plans to equip " Diego Silang " and her sister ships with new radar systems and long - range BGM - 84 Harpoon anti - ship cruise missile s , but this upgrade did not materialize due to the worsening political and economic crisis in the Philippines in the mid - 1980s .