BRP Sierra Madre (LT-57) is an LST-542-class tank landing ship that is an active duty[2] commissioned vessel under the Philippine Navy.

[5] Recommissioned on 20 August 1966 at the Mare Island Navy Yard, Vallejo, California,[citation needed] Harnett County saw extensive service during the Vietnam War.

[5] Over the course of her service in Vietnam, the crew of Harnett County was awarded two Presidential Unit Citations for "extraordinary heroism" and "superb" performance.

[5] The United States transferred Harnett County to the Republic of Vietnam Navy under the Security Assistance Program on 12 October 1970 and renamed RVNS My Tho (HQ-800).

[5] During the fall of the South Vietnamese capital, My Tho was fully loaded with more than 3,000 refugees from the city and set sail downriver towards the sea.

In exchange for the assistance in harboring the South Vietnamese, the United States brokered an agreement by which it would ensure that all operable ships moored at Subic Bay would transfer ownership to the Philippines.

[6] In 2013, The New York Times visited the site and reported on the life of the handful of marines stationed there, and the vessel's role in the geopolitics of the South China Sea.

[9] On 1 April 2014, the Philippine Navy succeeded in getting a fishing boat with resupply and replacement marines past the Chinese blockade.

"[12] In July 2015, Philippine Navy spokesman Colonel Edgardo Arevalo said that they were doing maintenance repair on the ship to ensure its minimum habitability.

[14] On February 6, 2023, the Chinese Coast Guard used what the Philippines Navy described as a military grade laser to temporarily blind crew.

The Philippine government aimed to improve the living conditions inside the ship by repairing the existing sleeping quarters, adding a modern kitchen, and access to the internet.