USS PGM-18 was a PGM-9-class motor gunboat built for the United States Navy during World War II.

She was built and originally commissioned as USS PC-1255, a PC-461-class submarine chaser, and was decommissioned and converted in late 1944.

USS PGM-18 struck a mine off the coast of Okinawa in April 1945; 13 men lost their lives when PGM-18 sank.

[1][2] She was decommissioned in October 1944 and converted into a gunboat at the Dade Dry Docks Shipyard in Miami, Florida.

[1] After being commissioned as USS PC-1255, the subchaser received her captain, Lieutenant John C. Bigham, Jr., USNR.

The next day PC-1255 received orders to report to the Dade Dry Docks Shipyard to undergo conversion from a submarine chaser into a patrol gunboat.

[1] After a week of shoreleave, she proceeded to Kerama Retto, Ryukyu Islands with a group of YMS-1 class minesweepers.

Eyewitnesses on nearby ships reported that the explosion was so powerful they could see five feet of sunlight under her keel before she came back down into the water, rolled over, and then foundered.