The Stanvac Dump is an unusual industrial artificial reef off the former Port Stanvac oil refinery, south of Hallett Cove. When the refinery was operating, surplus equipment was dumped at sea on a rocky seabed in 10-15 m, and it has since become a haven for fish. The Sea Wolves list trucks, pontoons, barges and extensive cabling among the debris, and the Dive Shack describes metal fragments, steel cable and pipes with obscure right angles.

The Marine Life Network notes that a refinery exclusion zone marker stands in the middle of the site. The appeal is the combination of odd man-made shapes and natural reef. The structures give shelter and the rocky seabed underneath already supports growth, so the site holds blue devils, cowfish, perch, morwong and old wives, with nudibranchs on the encrusted metal.

Photographers enjoy the contrast between marine growth and recognisable industrial objects. It is a site to dive carefully. The debris includes sharp metal and loose steel cable, so good buoyancy and a cutting tool are important, and gloves may be worthwhile.

Visibility is variable. The refinery closed in 2003 and the jetty was demolished in 2016, but an exclusion zone around the old port has remained; divers should check current maritime restrictions before visiting and stay outside any closed area. Stanvac Dump suits Open Water divers comfortable with boat diving and interested in something different from the classic Adelaide wrecks, and it can be combined with the nearby Stanvac Mooring Blocks or Barges on a trip from O'Sullivan Beach.

Boat access only. The usual launch is the O'Sullivan Beach boat ramp (off Galloway Road, O'Sullivan Beach; multi-lane ramp with breakwater, large trailer park and toilets), about 30 minutes' drive south of the Adelaide CBD. From the ramp run north along the coast to the GPS mark.

There are no public moorings: anchor in sand clear of the structure and keep a boat attendant on board with a dive flag, as fishing boats work these sites heavily. Charters from Adelaide Scuba and club boats sometimes use Glenelg or West Beach instead.

Like the rest of the metro coast, these sites face west into Gulf St Vincent and are best in offshore easterly winds, which are most common on summer and autumn mornings and on clear winter days. Westerly and south-westerly winds build chop quickly and make anchoring and recovery uncomfortable; the summer south-westerly sea breeze typically arrives late morning to early afternoon. Tidal streams in the gulf are modest but noticeable offshore on spring tides; neap 'dodge tide' days, when the water barely moves, give the easiest diving.

Visibility is usually better than at Glenelg because there is less river and stormwater influence, but drops after strong westerlies. Being further offshore, the deeper sites need a genuinely calm forecast.

Anchor on the mark, then explore the scattered structures in a loop at 12-14 m, keeping the compass handy because the debris is spread out. Avoid swimming through tangles of cable.

No regular charter; club and private boats from O'Sullivan Beach.