The USCGC Bibb is a 327-foot Treasury-class cutter resting on her starboard side at 105 to 130 feet — the sister ship to the Duane, sunk the very next day, just half a mile away. Less visited than her upright neighbor, better preserved for it, and a genuine bucket-list dive for advanced divers who make the effort.
On November 27, 1987, the USCGC Duane slipped beneath the surface off Key Largo and settled perfectly upright on the sand at 120 feet — a textbook artificial reef sinking. The very next day, her sister ship the USCGC Bibb went down using the exact same method. Whatever governs these things, she landed on her side.
Both ships were built in the mid-1930s as Treasury-class Coast Guard cutters — 327 feet long, 40-foot beam, capable of 20 knots, and built for the open Atlantic. The Bibb served through World War II, participating in convoy escort duty and Atlantic patrols. Decommissioned in 1985, she and the Duane were donated to the Florida Keys and sunk together as a pair of artificial reefs less than half a mile apart. The Duane gets the divers. The Bibb gets the marine life.
Because the Bibb rests on her starboard side, the shallowest accessible part of the wreck — the port gunnel railing — sits at around 105 feet, with the hull descending to 130 feet on the sand. The sideways orientation changes everything about how you experience a wreck this size. Passageways that would normally run horizontally now run vertically. Decks become walls. The crow's nest, which stretches away from the main hull, lies in the sand — and has been flying a Jolly Roger flag at its end for years, a detail divers who make it this far tend to remember. The swim-throughs are real but require careful navigation; entanglement from cables and wires is a genuine hazard, and the depth combined with the Gulf Stream current — which can pin divers against the hull or pull mooring buoys underwater on bad days — earns the site's Advanced-only designation honestly.
What the Bibb lacks in accessibility she makes up for in condition. The lighter traffic has left her hull relatively pristine compared to the Duane, and the Gulf Stream nutrients have produced dense coral and sponge encrustation across the superstructure. Goliath Grouper, Bull Sharks, and schools of Barracuda are regular presences. On good-visibility days, with the current cooperating, there may not be a better wreck dive in the Upper Keys.
Year-round — conditions highly variable; best in calm weather with light current
Calm seas, minimal Gulf Stream current — always verify conditions before departure. Site can be undiveable in strong current.
Strong and unpredictable — Gulf Stream proximity means current can be extreme. Experienced current diving skills required.
75–85°F depending on season
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