USS Castle Rock (AVP-35) was a United States Navy Barnegat-class small seaplane tender in commission from 1944 to 1946 which saw service in the late months of World War II.

Castle Rock stood out of San Diego, California, on 18 December 1944 bound for Pearl Harbor, Hawaii, and Eniwetok, where she arrived on 28 January 1945.

Her seaplanes carried out varied air operations, including reconnaissance, search, and antisubmarine warfare activities, while Castle Rock herself also performed local escort duties.

On 28 November 1945, Castle Rock sailed from Saipan for Guam, where she embarked a group assigned to study Japanese defenses on Chichi Jima and Truk.

She was decommissioned there on 6 August 1946 Barnegat-class ships were very reliable and seaworthy and had good habitability, and the Coast Guard viewed them as ideal for ocean station duty, in which they would perform weather reporting and search and rescue tasks, once they were modified by having a balloon shelter added aft and having oceanographic equipment, an oceanographic winch, and a hydrographic winch installed.

After undergoing conversion for use as a weather-reporting ship, she was commissioned into Coast Guard service as USCGC Castle Rock (WAVP-383) on 18 December 1948 at Mare Island Navy Yard, Vallejo, California.

In March 1956, Castle Rock towed the Finnish merchant ship Sunnavik from 300 nautical miles (560 km) south of Halifax, Nova Scotia, Canada, to safety.

On 22 and 23 February 1967 she rescued eight people from the sinking fishing vessel Maureen and Michael 90 nautical miles (170 km) southwest of Cape Race, Newfoundland, Canada.

While on an R & R visit from South Vietnam, she suffered an engineering casualty and sank at her pier in Singapore, but returned to duty with the squadron upon completion of repairs.

The squadron's other Vietnam War duties included fire support for ground forces, resupplying Coast Guard and Navy patrol boats, and search-and-rescue operations.

On 16 January 1974, the South Vietnamese frigate RVNS Lý Thường Kiệt (HQ-16) spotted Chinese forces ashore on the islands.

Reinforcements arrived for both sides over the next three days, including Trần Bình Trọng, which appeared on the scene on 18 January 1974 with the commander of the Republic of Vietnam Navy, Captain Hà Văn Ngạc, aboard.

On 22 and 23 May 1975, a U.S. Coast Guard team inspected Trần Bình Trọng and five of her sister ships, which also had fled to the Philippines in April 1975.

"[4] After Trần Bình Trọng had been cleaned and repaired, the United States formally transferred her to the Republic of the Philippines on 5 April 1976.