The Clan Ranald is one of South Australia's great wreck dives and a site of real historical weight. Built in 1900 at Sunderland by William Doxford & Sons, she was a turret-deck steamer, an unusual experimental hull form with a narrow raised 'turret' along the centreline designed to reduce Suez Canal tolls, which were charged on deck width. She was 108 m long with a 13.9 m beam and 3,596 gross tons.

In January 1909 she loaded 39,862 bags of wheat and 28,451 bags of flour at Port Adelaide, with extra coal stowed on deck. On 31 January, soon after leaving, a list to starboard steadily worsened and near Troubridge Point it suddenly increased to about 45 degrees. That night she capsized roughly 700 m from shore.

Forty of her 64 crew died, many of them Indian lascars, and a number are buried in the Edithburgh cemetery. The subsequent inquiry blamed overloading and poor stability, and the disaster contributed to changes in loading regulations. The wreck was rediscovered by volunteers in 1962, and in 1983 the Troubridge Hill Aquatic Reserve was declared around it.

An anchor was mounted on the clifftop in 1975 as a memorial. The ship lies upside down on sand in about 18-21 m, bow pointing east-south-east, her hull slowly collapsing onto the boilers. Divers swim along the upturned keel and around the sides, where gaps under the gunwales and collapsed plating reveal machinery and structure.

The Dive Shack calls it one of the best wreck dives in South Australia. After a century on the seabed it is a dense reef in its own right: boarfish, snapper, bullseyes, old wives and leatherjackets school around it, blue groper patrol, and large crayfish – protected in the reserve – shelter under the hull plates. Depth, current and open-water location make it a dive for experienced, advanced-certified divers.

It is also a war-grave-like site for many families and a protected historic shipwreck, so treat it with respect.

Launch at the Edithburgh boat ramp and run south-west along the coast past Troubridge Hill; the wreck lies about 700 m off the cliffs where one of its anchors is mounted as a memorial. The trip takes 25-30 minutes in a small boat. GPS is essential.

There is no shore access. The Troubridge Point reef is immediately inshore and makes a natural second dive.

Troubridge Point and the reefs south-west of Edithburgh face Investigator Strait and pick up southerly and south-westerly swell that wraps in from the Southern Ocean past Kangaroo Island. Anything over about 1-1.5 m of southerly swell produces heavy surge on the drop-off and poor visibility, and strong south-westerly winds make the boat run from Edithburgh rough. The best days follow a few days of northerly or light north-westerly winds, which flatten the sea along this coast; February-April with a prevailing northerly is the classic window.

Tidal streams in the strait can run strongly on spring tides, so plan around neaps or the turn of the tide. Currents across the wreck can be strong at times, so time dives for slack water where possible.

Descend to the upturned hull, orient on the bow (pointing east-south-east), and swim along the keel line to the stern, then drop to the sand to look under the gunwale at the collapsed sections and the starboard boiler. Keep well clear of confined spaces under the hull, return to the shot and do a safety stop at 5 m.

Recreational air dive; nitrox (EAN32) useful for extended bottom time. Collapsing hull – do not enter voids beneath it.

No resident operator; Adelaide shops (The Dive Shack, Diving Adelaide) and clubs run Yorke Peninsula boat weekends several times a year, and private boats dive it from Edithburgh on calm days.