Two light ships – small, heavily built vessels that once carried navigation lights to mark shoals and channels – were retired and sunk as part of the Cochrane Artificial Reef. Marinelife.org.au lists two light ships among the structures on the reef, and GoodDive gives the site as '2 Light Ships', placed in 2000 in about 18 m, with abundant marine life.

Light ships make good small wrecks: they are short and round-hulled, so each can be circled in a few minutes, leaving time to look closely at the growth on the hull and the fish sheltering beneath it. Two decades underwater have covered them in sponges, soft coral and algae. Expect the same cast as elsewhere on the Cochrane reef – estuary cod and gropers, schools of baitfish, wobbegongs resting against the hull, turtles and stingrays on the sand – and perhaps a manta ray passing in winter.

Information about these structures is limited to brief listings; their exact layout, orientation and position are not published, so dives here are usually guided by Bundaberg Aqua Scuba or by locals who hold the marks. At 18 m on the sand they suit Open Water divers with good air consumption, and Advanced divers on nitrox will get a longer look.

The light ships are a good second dive after the larger Ceratodus II or combined with the aircraft if visibility is good enough to swim between structures. As with every structure on this reef, look out for fishing line and do not enter enclosed spaces.

Cochrane Artificial Reef lies about 3 nautical miles off the rocky Woongarra coastline east of Bargara. Charter and private boats launch at the Burnett Heads boat ramp beside the Port of Bundaberg (15 km north-east of Bundaberg on Burnett Heads Road; large trailer park, toilets). From the Burnett River entrance it is a short run south-east – roughly 20-30 minutes in a small boat.

The reef covers an area of about 400 x 800 m, and each structure has its own GPS mark, so boats either pick up a buoy where one is present or anchor in sand beside the target structure (never on the wreck). Bundaberg Aqua Scuba runs boat dives here when the weather allows; others come by private boat.

The reef is in open water off the Woongarra coast, partly sheltered from southerly ocean swell by K'gari but exposed to south-east trade winds and north-easterly sea breezes. Operators generally want winds under about 15 knots and seas under 1 m. Visibility averages 8-12 m and is best in winter (May-September) with light westerlies; it falls sharply after heavy rain as the Burnett and Elliott rivers flush brown water along the coast, typically in the December-March wet season.

Tidal current is usually mild but can run on big spring tides – dive around slack water on neaps for the clearest, calmest conditions. Manta rays pass through in winter.

Descend to the sand at about 18 m beside the first light ship and swim around it, then follow a compass bearing to the second if they are close. Look under the rounded hulls for cod and wobbegongs. Ascend the line with a safety stop.

Bundaberg Aqua Scuba (Bourbong St, Bundaberg) – boat dives to Cochrane Artificial Reef when weather permits, typically weekends or on demand; otherwise private boats from Burnett Heads. Fishing charters use the reef heavily.