The HA Lumb is a small steel tug with a long history. According to the Marine Life Network she was built in 1943 by the Decatur Iron and Steel Company of Alabama for the US Navy, about 24 m (78 ft) long, and later came to South Australia where she was converted to a fishing trawler at Port Lincoln. In 1994 the Dive Industry Association of SA prepared and scuttled her off Port Noarlunga as a purpose-built dive site, next to the existing Noarlunga Tyre Reef.

She sits in about 20 m on a fine silty seabed. Holes were cut in the deck to allow safe, easy penetration, and the Federation notes these give straightforward access to the interior for trained divers. The hull is open but partly silt-filled, so fin technique matters.

Thirty years of growth have covered the steel in sponges and ascidians, and the wreck is noted for its many nudibranchs. Leatherjackets, morwong and schools of small fish shelter around the hull, with fish numbers varying from dive to dive. The real appeal is the combination.

The MV Seawolf lies only 15-20 m away, and the Noarlunga Tyre Reef spreads out alongside, so a single dive can take in two wrecks and an artificial reef, making the Noarlunga complex one of the best-value boat dives in Adelaide's south. The short 5-minute run from O'Sullivan Beach adds to its appeal. The Lumb suits Advanced divers wanting a small, manageable wreck with easy penetration, and nudibranch photographers.

It is also a good step between shallow reef diving and the deeper Stanvac Barges or Hobart.

Boat access only. Launch at the O'Sullivan Beach boat ramp (off Galloway Road; large trailer park, toilets) and run about 5 minutes south to the Noarlunga artificial reef, roughly 2.5-3 km west of Port Noarlunga jetty. The HA Lumb, MV Seawolf and Noarlunga Tyre Reef lie together, so one anchor or shot can serve all three.

There are no public moorings; anchor in sand beside the wrecks, not on them, and leave a boat attendant with a dive flag. Operators from Adelaide sometimes run here from Glenelg on days when Holdfast Bay is poor.

The Noarlunga artificial reef sits in open gulf water off the southern metro coast. It is diveable in light winds, ideally easterlies or light northerlies; westerly and south-westerly winds build steep chop quickly and the summer sea breeze usually arrives late morning to early afternoon. Tidal currents are usually mild but noticeable on spring tides – neap dodge tides are best.

The seabed is fine silt, so visibility varies greatly: up to 15 m after calm weather, but much less after westerly blows, after rain (Onkaparinga River plume) or when divers stir the bottom. Being close to O'Sullivan Beach, it is a good fallback when further sites are too rough.

Descend to the HA Lumb, circle the hull at 20 m and look through the cut deck holes. Swim 15-20 m to the Seawolf (lying astern and slightly to starboard), circuit it, then finish on the tyre modules at 18 m before returning to the anchor for a safety stop. Keep fins high off the silt.

Air or EANx 32. Penetration via cut deck holes within wreck training limits; interior silts easily.

Club boats (Sea Wolves, Underwater Sports) and Adelaide shop boats run occasional trips, usually combined with the Seawolf; frequently dived from private boats out of O'Sullivan Beach.