Dozens of sailors are missing after a Thai navy warship capsized and sank in rough seas in the Gulf of Thailand on Sunday. A search and rescue mission was launched Monday to find 31 crew members missing after the HTMS Sukhothai sank. Local authorities said over 100 crew were on board, with 75 being successfully rescued on Monday. Officials said the vessel took on water which flooded its power controls leaving the crew unable to control the ship shortly before it capsized at around 11:30 p.m. Sunday. The Royal Thai Navy has launched an investigation. The Sukhothai was built in the U.S. in the 1980s before entering service with the Thai Navy.