Nhut Tao was sunk in early 1974 during an engagement between Republic of Vietnam Navy forces and those of the Chinese People's Liberation Army Navy in a dispute over control of the Paracel Islands. During the Battle of the Paracel Islands, Nhut Tao took a direct hit from a ship-to-ship missile on her bridge and went dead in the water. On fire with her guns silent, crew from below deck cleared the guns and renewed the fight. The Chinese again concentrated fire on Nhut Tao and again her guns fell silent as she began to sink. A few days later a Dutch tanker and a Vietnamese fishing boat pulled 37 survivors of the sunken Nhut Tao out of the South China Sea.
http://en.wikipedia.org/wiki/Battle_of_the_Paracel_IslandsThe battle
In the early morning of January 19, 1974, Vietnamese troops from HQ-5 landed on Duncan Island (Quang Hòa in Vietnamese) and came under fire from Chinese troops. Three Vietnamese soldiers were killed and two others were injured. Outnumbered, the Vietnamese ground forces withdrew by landing craft, but their small fleet itself did not: instead, they drew up close to the Chinese ships in a tense standoff.
At 10:24 a.m., two Vietnamese ships, HQ-16 and HQ-10 opened fire against Chinese ships. Then, HQ-4, HQ-5 did the same thing. The ensuing sea battle lasted for about 40 minutes, with numerous vessels on both sides sustaining damage. The Chinese succeeded in damaging all four Vietnamese ships, particularly the HQ-10. The Nhật Tảo (HQ-10) could not retreat because her last working engine was disabled in the battle: the ship's crew was ordered to evacuate, but her captain, Major [navy lt. commander] Ngụy Văn Thà, remained under fire and went down with his ship. HQ-16, severely shot by a friendly ship, the HQ-5, was forced to retreat westwards. Meanwhile, HQ-4 and HQ-5, were forced to retreat.
The next day, Chinese jet fighters and ground-attack aircraft from Hainan bombed the three islands, and were followed up with an amphibious landing force. The South Vietnamese Marine garrison was captured, and the naval force retreated to Đà Nẵng.
While the battle was going on, the Vietnamese fleet detected two Chinese reinforcing warships rushing to the area; China later acknowledged that these were the Hainan-Class submarine chasers #281 and #282. Despite reports that at least one Vietnamese craft had been struck by a missile, China insisted that no missile-bearing ships were involved in the battle. In addition, the South Vietnamese fleet also received warnings from the United States that their naval radar had detected additional Chinese guided missile frigates and MIG jet fighters on their way from nearby Hainan. South Vietnam requested assistance from the US Seventh Fleet, but the request was rejected.