The Southern Cross was a 640-gross-ton steel passenger steamer built in 1863 at Govan, Scotland. She ran aground near Boat Rock in 1889 when bushfire smoke obscured the Rocky Cape light. The Marine Life Network guide rates the wreck 6 out of 10: heavily broken and scattered over about 50 square metres in 4-12 m, with a largely intact stern and visible propeller and varied artefacts in the gullies nearby. A sunken reef rises from 10 m to the surface close by. The site has been heavily souvenired and few artefacts remain. The Leven Scuba Club says the wreck of the Southern Cross is worth attempting. Local divers typically combine two or three Rocky Cape and Sisters Island sites in a day, choosing the side of the cape that suits the wind and the state of the tide.

The Rocky Cape and Sisters Island area is, in the Leven Scuba Club's words, the best collection of dive sites on the north-west coast. The quartzite of Rocky Cape - some of the oldest rock in Tasmania - forms gutters, ledges, caves and bommies, and the tidal flow along Bass Strait keeps sponges, gorgonians, sea pens and bryozoans well fed. Michael McFadyen, diving here in February 2008, recorded 18-19 °C water and 20-25 m visibility, figures that surprise divers used to the east coast.

Rocky Cape National Park also protects Aboriginal cave sites and coastal heath above the water, and a Parks Pass is required for vehicles. The nearest hyperbaric chamber is the Royal Hobart Hospital, about four hours' drive away, so conservative profiles and oxygen on the boat are essential.

Rocky Cape National Park is off the Bass Highway between Wynyard and Stanley, about 30 minutes west of Wynyard and 1 hr 15 min west of Devonport (Spirit of Tasmania terminal). A Parks Pass is required. Boats launch at the Rocky Cape boat ramps (the western ramp at Mary Ann Bay suits boats up to about 5 m), Sisters Beach or Boat Harbour; ramps are shallow and weedy at low tide, so a 4WD tow vehicle helps.

Boat Rock lies east of Rocky Cape; launch at Rocky Cape or Sisters Beach and run to the rock (about 10-15 minutes). The wreck is 75-100 m WNW of Boat Rock.

The north-west coast faces Bass Strait: north-westerly to north-easterly winds and westerly swell make it rough, while southerly winds blow offshore and give flat seas - light airs and sunny days are relatively common from January to April. Easterly gales are common in the warmer months and close the eastern faces of Rocky Cape and Sisters Island. Tidal streams run along the coast (eastward on the flood), and several boat sites are only comfortable around slack water.

Dive about 2 hours after high tide for manageable tidal flow.

Locate the largely intact stern and propeller, explore the scattered wreckage over about 50 square metres and the nearby gullies, then finish at the pretty south-western end of Boat Rock. Turn the dive at half gas (thirds where current or overhead sections are involved), deploy an SMB before surfacing for the live-boat pick-up, and complete a 3-minute safety stop at about 5 m where depth allows.

No confirmed commercial dive operator on the north-west coast as of 2026 (older guides mention dive services in Wynyard and Devonport - verify). Sites are dived mainly by the Leven Scuba Club (Ulverstone), other north-west club members and visiting divers with their own boats; Tasmanian Divers (Launceston) runs occasional northern trips.