USS Oriskany

The 'Mighty O' fought two wars before becoming the largest ship ever deliberately sunk as an artificial reef. Completed after the Second World War to an improved Essex-class design, the Oriskany launched strikes through Korea and Vietnam; a magnesium-flare fire in 1966 killed 44 of her crew, and among her aviators was John McCain, shot down over Hanoi in 1967. Decommissioned in 1976 and slated for scrap, she was instead handed to Florida, cleaned of contaminants over years, and scuttled 22.5 miles southeast of Pensacola in May 2006 — the 'Great Carrier Reef.' She sits upright on sand at roughly 64 meters, and hurricanes have since settled her deeper into the bottom: the flight deck now lies near 44 meters, so recreational divers work only the island superstructure, which rises to about 24 meters, while the deck and hangar bays are the province of technical teams. Charters run from Pensacola and Destin, and on a clear day the tower emerging from blue Gulf water below a descent line is one of American diving's genuinely humbling sights.

How she sank: Deliberately scuttled as an artificial reef in the Gulf of Mexico off Pensacola, Florida, 17 May 2006.

Condition: Upright and structurally sound, settling gradually into the sand; lighter island fittings are corroding away

Penetration: Full With Training. Openings exist throughout the island and hull, but every enclosed space starts deep; interior work is technical diving, full stop, and the ship has claimed unprepared divers. Entering any overhead environment requires specific training — a wreck certification at minimum, technical wreck training for full penetration.

Recommended certification: Deep specialty for the island; technical training for the flight deck and below

Current: Moderate · Visibility: 10–30 m

Marine life: Amberjack and almaco jack swarm the tower, red snapper crowd the flight deck, sandbar sharks and the occasional whale shark cruise past, and baitballs sheet across the island in summer.

Hazards: Serious depth, open-water current, monofilament from fishing boats, and an interior far beyond recreational limits

Florida state artificial reef; removing anything from the former warship is prohibited