The SS Bombo is the best-known wreck of the Illawarra and one of the more poignant. Built in 1929 by H. Robb at Leith in Scotland, the 46 m, 540-ton steel collier spent the 1930s carrying crushed blue metal from the Kiama quarries to Sydney. From 1941 to 1946 she served as the auxiliary minesweeper HMAS Bombo before returning to the stone trade. At about 10 pm on 22 February 1949, loaded with some 640 tons of blue metal, she was caught by a southerly storm about 4 km from Port Kembla; the cargo shifted, she rolled over and sank within minutes. Twelve of her fourteen crew, including Captain Arthur Bell and Chief Engineer Percy Carroll, were lost.

The wreck was located in 1978 by Don Morrison and Bruce Hammond and was then remarkably intact apart from a break in the hull. She lies upside down in 32 m, roughly north–south, on a sand bottom. Storms, especially a major one in 1996, have changed her dramatically: the hull has split open and the stern has broken away and now sits upright on the seaward side, carrying the propeller with one blade snapped off. The collapse has exposed the inverted engine – pistons, conrods and driveshaft are easy to see – and the boiler can be viewed from both sides of the hull. Along the sides lie the hopper, a bollard, pieces of hatch cover and the rudder. The bow still shows scarring from the sinking.

Penetration, once possible through several openings, is now limited and unwise because of the unstable structure. The wreck attracts schools of yellowtail and bullseyes, with nannygai, wobbegongs, red morwong and moray eels around the debris. The combination of depth, variable visibility and commercial shipping means this is a dive for experienced divers who can manage a short bottom time and a clean ascent in open water. It is also a war grave in spirit if not in law – treat it with respect.

Launch from the Port Kembla boat ramp in the Outer Harbour (behind the steelworks; large car and trailer park, toilets). Wollongong Harbour's ramp (Belmore Basin) is closer to the northern islands but suits only small boats in calm seas. From Port Kembla steer out through the harbour entrance, keeping clear of the shipping channel, and head for the island; the run is 10–15 minutes in a small boat.

The wreck is a short run north-east of the harbour entrance on GPS 34° 26.680' S 150° 55.546' E. Before leaving the ramp phone the Port Kembla port duty officer to confirm no ships are due in or out during your dive window – large bulk carriers pass very close to the site. United Divers in Wollongong can advise on current marks and arrangements.

Open coast site exposed to swell from the north-east through south; wants a swell under about 1.5 m and light winds for a comfortable anchor-up. Visibility on the wreck is notoriously variable and often does not match surface conditions – it can be 5 m on a glassy day and 15 m after a blow. An incoming tide is generally preferred, although tide is rarely critical.

After heavy rain, dirty water from Port Kembla harbour and Lake Illawarra can reduce visibility. The overriding constraint is shipping: dive only in a gap between vessel movements.

Anchor near the stern and descend to the engine and boiler area. Work along the eastern side of the inverted hull inspecting the 1996 storm damage, visit the broken-off stern section which now sits upright with the propeller (one blade missing), then return up the western side past the scattered hopper, bollard and hatch-cover pieces. Finish on top of the hull before ascending the anchor line; on air expect 15–20 minutes before decompression.

Nitrox (EAN28–30) extends no-decompression time usefully. Structure is unstable – no penetration.

United Divers (Wollongong) runs occasional boat trips when shipping and weather allow; otherwise dived from private and club boats (Sydney clubs make regular trips). No daily charter.