Flynn Reef (Tracy's Bommie)

Overview: Pristine Outer Barrier Coral Diversity

Situated 60km east of Cairns on the outer edge of the continental shelf, Flynn Reef is widely regarded by marine biologists as offering the healthiest coral cover on the central Great Barrier Reef.

The reef is famous for its signature sub-sites: Tracy’s Bommie, Gordon’s Mooring, and Tennis Court.

Detailed Dive Route: Tracy’s Bommie to Coral Gardens

• Tracy’s Bommie (10m–20m): A solitary, towering coral spire rising from 20m depth to within 3m of the surface. Blanketed in staghorn, plate corals, and giant clams (Tridacna gigas) whose iridescent blue and purple mantles span up to 1.2 metres wide.
• The Sand Gully & Turtle Alley (12m–16m): Weave through the coral channels connecting Tracy’s to Gordon’s Mooring. Resident green and hawksbill turtles graze undisturbed on soft corals.
• The Outer Drop-Off (18m–22m): Where the reef meets the open Coral Sea. Whitetip reef sharks patrol the wall while schools of yellowtail fusiliers and chevron barracuda shimmer in 25m+ visibility.

Logistics & Certification

• Access: Available via day boats and liveaboards from Cairns.
• Certification: Open Water (18m) for the main reef crest and bommies; Advanced Open Water (30m) for deep outer sand chutes.

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 22m)

• NDL Discipline: At depths of 22m, 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: Giant Potato Cod (Epinephelus tukula), Humphead / Maori Wrasse (Cheilinus undulatus), Grey Reef Sharks (Carcharhinus amblyrhynchos).
• Reef Fish & Keystone Species: Giant Clams (Tridacna gigas), Clown Anemonefish (Amphiprion ocellaris), Coral Trout (Plectropomus leopardus).
• Macro Biodiversity & Benthic Invertebrates: Mantis Shrimp (Odontodactylus scyllarus), Flame File Shells (Limaria fragilis), Leaf Scorpionfish (Taenianotus triacanthus).
• Elasmobranchs & Marine Reptiles: Whitetip Reef Sharks, Green Sea Turtles, Hawksbill Turtles, Seasonal Dwarf Minke Whales (Balaenoptera acutorostrata).