The SS Bonnie Dundee is a small, fish-covered wreck off Swansea with a tragic story. Launched by Gourlay Brothers at Dundee, Scotland, in March 1877, she was a 39 m, 121-ton steamer powered by a 40 hp twin-cylinder compound engine, with two masts. At about 8 pm on 10 March 1879, off Caves Beach, she was struck amidships on the starboard side by the larger steamer Barrabool, which holed her below the waterline.

She sank in about four minutes; COAST Magazine records that all the women aboard drowned. She now lies in about 35 m, 5.1 km off Caves Beach and 4.4 km from the Swansea Channel entrance, in two sections 25-30 m apart. The larger stern section is the main dive.

Michael McFadyen describes the boiler mostly clear of the sand, with a large steam dome and a small donkey boiler in front; behind it stands the compound engine, and at the stern the steering gear, rudder and propeller are visible, with much of the hull intact along this section. Between the boiler and the bow the hull has largely gone, leaving a small piece of plating to starboard and three or four ribs rising high above the sand to port. The bow section is about 5 m of ship tipped roughly 45 degrees to starboard.

Grey Nurse Charters calls the wreck a fish magnet, and McFadyen describes huge schools of yellowtail, nannygai and seapike hanging over it, with silver sweep, black reef leatherjackets, wobbegongs in the sand and large moray eels in the boiler and engine. At 32-36 m it suits Deep-certified divers with experience; nitrox extends the short no-deco time. It is the classic wreck dive of the Swansea area.

Boats launch from the public ramps inside Swansea Channel, either at Black Neds Bay beside the Swansea Bridge or at the Swansea/Lake Macquarie ramps, about 25 km south of Newcastle via the Pacific Highway. Parking with trailer bays is available at Black Neds Bay. The run is east along the channel, across the Swansea bar (check the bar and tide first - cross on the flood where possible) and a short distance out to the site; the Bonnie Dundee is about 4.4 km from the channel entrance and 5.1 km off Caves Beach, roughly 15 minutes from the ramp.

McFadyen's GPS list gives 33°06.4267'S 151°42.1700'E, with 35 m on the sand and the top at 32 m. The wreck is small and in two parts, so anchoring takes care.

Moon Island and the reefs off Swansea Heads sit just outside the Swansea Channel bar, which is the deciding factor on most days: the bar is dangerous in any sizeable easterly or south-easterly swell and on a run-out tide, and Marine Rescue Lake Macquarie should be checked before crossing. Offshore, the sites prefer swell under about 1.5 m and light westerly or northerly winds; a strong nor'easter makes the eastern walls choppy, and a southerly swell pushes surge into the caves. Visibility runs 8-15 m and is best on a flooding tide, when clean ocean water replaces the lake outflow; after heavy rain the brown plume from Lake Macquarie can cover the inshore sites for days.

Descend to the larger stern section with the boiler, donkey boiler and engine. Explore the steering gear, rudder and propeller, then, if time and visibility allow, cross the 25-30 m gap to the small bow section tipped 45 degrees to starboard. Return to the line and ascend with a safety stop.

Nitrox (EAN28-30) recommended. Protected historic shipwreck.

Grey Nurse Charters (Swansea) runs boat dives to the Moon Island and Swansea offshore sites most weekends and on demand; Dive Newcastle and local clubs also dive the area from private boats launched at Swansea.