The Duckenfield is the only genuine nineteenth-century shipwreck on the Northern Beaches at recreational depth, and its story is one of poor seamanship and remarkable salvage. Built in London by J. and W. Dudgeon in 1875, she was a 49 m iron screw steamer of 368 tons with a two-cylinder vertical engine, owned by J. and A.

Brown and employed in the Newcastle coal trade. On 24 May 1889, bound for Sydney with coal, coke and 50 tons of copper ingots, Captain Thomas Hunter held too close to the coast in heavy rain and ran her onto Long Reef. The crew got ashore; the Marine Board found the loss was caused by Hunter's default and suspended his certificate for six months.

Within weeks salvors Arthur Briggs and William May recovered 32 tons of copper for the underwriters using explosives, which is why the wreck is so thoroughly flattened. It was then forgotten until Alan and Neil McLennan relocated it in 1987. The remains lie roughly north–south with the bow to the north on a rock-and-sand bottom at 21–23 m off the seaward edge of Long Reef Point.

The most conspicuous piece is the twin-cylinder engine standing on its bedplate, with the driveshaft running aft to a rudder and a single surviving propeller blade. Nearby are the main boiler, a donkey boiler, a large winch, two salvage anchors dropped by the 1889 divers, and scattered copper ingots still fused into the bottom. Forward, the lower hull and ribs remain in the sand leading to the bow section, ship's anchors, chain and a davit.

Everything can be seen in one 35-minute dive. Fish life is typical of Long Reef: wobbegongs under the plates, blue groper, bullseyes in the boiler, morwong and the occasional cuttlefish. A permit was once required to dive the site but was dropped around 2004; it remains a protected historic shipwreck and nothing may be taken.

The Duckenfield suits Advanced divers who enjoy reading a broken wreck and want history close to the city, and it pairs naturally with the Long Reef Wall.

Boat only, on the seaward side of Long Reef Point about 1.5 km off the headland. Charters from Manly, Rose Bay and Roseville Bridge take 30–40 minutes; Pittwater boats about 40 minutes south. The site is on the edge of the Long Reef platform and is only diveable in low swell because the reef top shoals rapidly to the west.

Use the GPS mark and anchor on the engine, the most prominent target; there is no mooring. The whole wreck can be covered in a single dive.

Long Reef Point is the most exposed headland on the Northern Beaches and the wreck lies on its outer edge. Any south-easterly or easterly swell over about 1.2 m produces heavy surge across the site and breaking water on the reef top nearby; north-east sea breezes in the afternoon add chop. Choose a morning with under 1 m swell and westerly or light winds.

Visibility drops after rain when Dee Why and Narrabeen lagoons open. Winter westerlies give the flattest, clearest days.

Descend the anchor to the twin-cylinder engine at 21–23 m. Work north along the keel line past the driveshaft, single prop blade, winch and rudder to the boilers and donkey boiler, look for the remaining copper ingots and salvage anchors, then follow the ribs to the bow section, ship's anchors, chain and davit. Return along the other side of the hull to the anchor and ascend with a safety stop on the line.

Sydney Dive Charters and Dive Centre Manly include the Duckenfield as an occasional second dive after the Apartments/Long Reef Wall when swell allows; Pro Dive Manly visits irregularly. Also popular with private boats and club dives from Pittwater.