The Cheynes III is a small wreck with a large place in Australian diving history: scuttled by the South Coast Divers Club in 1982 (some sources say 1983), it is widely described as the first vessel purpose-prepared and sunk as a dive wreck in the southern hemisphere, predating the Swan and Perth by 15-20 years.

She was a 48 m, 440 t steel whale chaser built in 1943 and bought in 1963 by the Cheynes Beach Whaling Company, which operated Australia's last whaling station at Frenchman Bay across the sound. The chasers ran out of the station hunting sperm whales off the continental shelf until commercial whaling in Australia ended in November 1978. With the station closed, Cheynes III lay derelict until the dive club acquired her, stripped her and sank her on the western side of Michaelmas Island. Her sister chaser Cheynes IV is preserved on dry land at the Albany Historic Whaling Station, which makes a good pairing for divers interested in the history.

After more than 40 years underwater the wreck still sits upright on sand at around 19-23 m, but the midships section has collapsed and penetration is now considered unsafe; the wheelhouse and engine room areas that older guides describe can be looked into but not safely entered. The hull is thick with sponges, soft corals, ascidians and anemones and holds a dense population of fish: boarfish, morwong, blue groper, bullseyes, old wives, silver drummer, leatherjackets and schools of scad, with snapper, jewfish, kingfish and samson fish cruising the edges.

It is a compact, relaxed dive that an Open Water diver can cover comfortably in one tank, and a good second dive after the Perth. Visibility is rarely spectacular, but the density of life and the history make it worthwhile.

Albany is 418 km (about 4.5 hours) south-east of Perth via Albany Highway. Charter boats and private boats launch either from the Emu Point boat ramp (Emu Point Drive, 7 km north-east of the CBD, with a large trailer car park, toilets and a fish-cleaning station) or from the town ramp beside the Albany Waterfront marina in Princess Royal Harbour, which exits into King George Sound through the harbour entrance past Possession Point. From Emu Point the wreck is roughly 6 km (10-15 minutes) south-east across the sound; from the town ramp allow 25-30 minutes.

The wreck lies off the western end of Michaelmas Island and is usually marked by a mooring or found on a GPS mark (S 35° 02.653', E 118° 01.629'). No permit is needed to dive it from a private boat. Charter divers go with South Coast Diving Supplies, which often pairs it with a Michaelmas or Breaksea reef dive.

King George Sound is sheltered from the Southern Ocean by Flinders Peninsula, Bald Head and Breaksea and Michaelmas Islands, which is why Albany can offer diving on days when the open coast is wild. The Cheynes III is protected from everything except strong southerly to westerly winds, which funnel into the sound between Vancouver Peninsula and Michaelmas Island and make the site rough; divingwawrecks lists swell under 1.5 m as the diveable limit. North-easterly sea breezes on summer afternoons can also chop it up, so morning dives are preferred.

Visibility is typically 5-12 m and is worse after winter rain when harbour run-off drifts across the sound.

Descend to the upright hull at about 15-18 m and circle it at deck level, starting at the bow and harpoon platform area and working aft past the collapsed midships to the stern and propeller area on the sand at 19-23 m. Look into the openings with a torch but do not enter. Return along the other side, then ascend the line or make a controlled ascent with a safety stop.

South Coast Diving Supplies (Albany) – the town's dive shop; runs scheduled boat dives in King George Sound most weekends and on demand in summer/autumn, and issues HMAS Perth permits; Perth Scuba includes it on Albany weekend trips.