This image has it all, and you can almost smell the saltwater and burnt propellant. Note the assorted seagoing tattoos, Dixie cup hats, total lack of eye and ear pro, and the assistant gunner with his burning stogie.
USCG Photo 26-G-508. National Archives Identifier: 205572937
Original caption: On the target are these alert, fighting Coast Guardsmen aboard a Coast Guard ‘Sub-Buster’ somewhere on the Atlantic. Discharged shells fall to the deck from their spitting gun.
From the looks of that bronze one-piece deckhouse and the water-cooled .50 cal, the vessel in question is one of the early 83 footer “Jeep of the Deep” patrol boats used by the Coast Guard in WWII.