The Royal Shepherd is one of the oldest steamships diveable in Australia and the best example of an early marine steam engine on the sea floor anywhere in the country. Built in 1853 by Blackwood and Gordon at Paisley, she was a 42 m, 331-ton iron screw steamer with a twin-cylinder oscillating engine, first employed between Melbourne and Launceston and then passed through a long succession of owners on the east coast. On the night of 14 July 1890 she was leaving Sydney when the heavily laden collier Hesketh, inbound, struck her; she sank in ten minutes 750 m off South Head.

The Hesketh's master was found at fault and lost his certificate for six months. Almost nothing of the hull survives. What sits upright on the sand at 27–30 m is the machinery: a square boiler, the compound engine – unusually inverted, with the cylinders below the crankshaft – a large flywheel, the driveshaft running aft to the propeller, and, about 15 m away, a deck winch.

Michael McFadyen calls it 'the best presented example of an early steam engine in Australia', and photographers treat the engine as a sculpture. Iron frames and scattered plate lie around, half-buried. Fish life is not prolific but is dependable: moray eels in the engine, cuttlefish, bullseyes under the boiler, several species of leatherjacket and small flathead on the sand; Port Jackson sharks visit in winter and kingfish occasionally sweep past.

Visibility is often surprisingly good because the site is flushed by clean ocean water on the flood tide. Its position in the lee of South Head means it is dived most when a southerly is blowing, which has made it a fixture on Manly and Rose Bay charter schedules. The Royal Shepherd suits Advanced divers with an interest in engineering and history, and it is a protected historic shipwreck – nothing may be removed.

Boat only, 750 m off South Head just outside the Heads; 10 minutes from Rose Bay wharf or Watsons Bay, 15 minutes from Little Manly. The southern mark is the Watsons Bay church spire on the cliff edge; GPS 33°50.14'S 151°17.27'E (WGS84). McFadyen's GPS list notes the wreck is currently moored; otherwise anchor beside the boiler, which is the sounder target.

Sydney Dive Charters and Dive Centre Manly run it as an Advanced boat dive from Little Manly/Rose Bay.

Sitting in the lee of South Head, the Royal Shepherd is relatively protected from southerly winds and swell and is the standard fallback when the open-coast sites are blown out; it is exposed to north-easterly chop and easterly swell. Visibility follows the tide – clean ocean water on the last of the flood (25 m has been recorded two hours before high) and dirty harbour outflow on the ebb, with several bad days after heavy rain. Depth limits bottom time, so nitrox is worthwhile.

Ships and ferries use the entrance constantly; ascend on the line.

Descend the line to the boiler at 27 m. Examine the square boiler and the inverted compound engine with its big flywheel, follow the driveshaft aft to the propeller at 30 m, then swim about 15 m to the separate deck winch and back. Look for morays and cuttlefish in the machinery.

Return to the line at 20–22 minutes and ascend with a long safety stop.

Nitrox 32% recommended.

Sydney Dive Charters – regular Advanced boat dives ('Royal Sheppard wreck, 28 m'); Dive Centre Manly and Pro Dive Manly on their Heads rotation, often as the deep first dive when a southerly makes the ocean sites rough; Abyss and Frog Dive on club days.