USS Spiegel Grove

Overview: The 510-Foot Artificial Reef Titan

Located 6 miles off Key Largo within the Florida Keys National Marine Sanctuary, the USS Spiegel Grove (LSD-32) is one of the largest ships ever intentionally scuttled as an artificial reef.

At 510 feet (155 metres) in length and 84 feet wide, the Thomaston-class dock landing ship served the US Navy from 1956 to 1989. Scuttled on 17 May 2002, she originally came to rest on her starboard side in 130 feet (40m) of water, before Hurricane Dennis in 2005 miraculously righted the massive ship onto her keel!

Detailed Dive Profiles & Depth Zones

• The Main Flight Deck & Superstructure (18m–26m): Open Water and early Advanced divers can explore the massive open flight deck, crane booms, and radar masts, where Goliath groupers (Epinephelus itajara) weighing up to 200kg shelter under deck overhangs.
• The Gun Mounts & Bridge (24m–30m): Exploring the forward bridge, pilot house, and twin 3-inch gun mounts adorned with yellow tube sponges and encrusting corals.
• The Sand & Propeller Well (38m–40m): Deep and technical divers can descend to the keel resting upright on the sandy seabed at 40 metres.

Current & Safety Warning

• Gulf Stream Current: The Florida Current often washes across the Spiegel Grove at 1.5 to 3.0 knots.
• Descent Line Discipline: Always descend and ascend using the designated mooring buoy down-lines. Never attempt a free-floating descent without a line in strong current.
• Certification Required: Advanced Open Water (30m) recommended; Enriched Air Nitrox 32% is essential to extend allowable bottom time at 25m–30m depth.

Technical Dive Profile & Navigation

1. Entry & Descent Mechanics

• Descent Method: Direct giant-stride or negative back-roll from the boat, descending along the shot line to prevent surface drift.
• Ear Equalization: Equalize continuously every 1 metre during the descent phase to prevent sinus or middle-ear barotrauma.
• Compass Heading & Navigation: Set a primary heading toward the main reef structure. Maintain buddy contact within 2 metres throughout the descent.

2. Deep Section & Gas Management (14m to 40m)

• NDL Discipline: At depths of 30m, your No-Decompression Limit ticks down rapidly. Monitor your dive computer continuously.
• The Craig Rule: Divers certified to Open Water level (18m maximum) must stay on the upper reef shelf and never follow advanced divers down past 18m.
• Turnaround Gas: Signal your buddy and start your ascent when the first diver reaches 110 bar (or one-third of usable cylinder capacity).

3. Ascent & 5m Safety Stop

• Ascent Rate: Ascend along the reef wall at a controlled rate not exceeding 9 metres per minute.
• Mandatory Safety Stop: Complete a strict 3-to-5-minute safety stop at 5 metres (15 feet) before deploying an SMB and surfacing with a 360-degree overhead scan.

Marine Life & Habitat Zones (Biologically Verified)

• Apex & Pelagic Predators: Goliath Groupers (Epinephelus itajara), Great Barracuda, Blacktip Sharks (Carcharhinus limbatus).
• Reef Fish & Keystone Species: Yellowtail Snapper (Ocyurus chrysurus), Porkfish (Anisotremus virginicus), Blue Tang (Acanthurus coeruleus).
• Macro Biodiversity & Benthic Invertebrates: Spotted Morays (Gymnothorax moringa), Banded Coral Shrimp (Stenopus hispidus), Flamingo Tongues.
• Elasmobranchs & Marine Reptiles: Atlantic Nurse Sharks, Loggerhead Turtles (Caretta caretta), Southern Stingrays.