Not sure what this patrol boat this is that came out to see us on the Sherman.. ... In researching the Hull number = 612 RVNS Thái Bình (HQ-612) 1966 PGM-72 The PGM-9-class gunboats were built in the U.S. and transferred on completion to South Vietnam. They were assigned hull numbers, but not commissioned into the United States Navy. They were 122 ton, 100-foot (30 m) vessels, with a top speed of 17 knots (31 km/h; 20 mph) and armed with one 40 mm gun, two 20 mm guns and an 81 mm mortar.