sentences:  At the end of March 1975, the ARVN maintained a security team on Phú Quý, which included one police platoon and 4,000 members of the civilian self-defense forces.From April 1975, the local ARVN forces on Phú Quý were joined by an additional 800 ARVN soldiers, who escaped from the mainland town of Hàm Tân when North Vietnamese forces captured it.On April 22, the RVN deployed the "HQ-11" corvette and one small patrol boat to defend the island from the North Vietnamese onslaught.