Hardie Artificial Reef is the sister reef to Simpson: around 15 reinforced concrete modules of up to 24 tonnes each, set in five clusters of three, but spread over a larger area of about 160 ha. It lies about 2 nm north-east of Little Woody Island, towards the western shore of K'gari near Bogimbah Creek, in 10-16 m. It is named after Peter Hardie, Big Woody Island's longest-serving lighthouse keeper.

Like Simpson, the reef was designed for recreational fishing, but Hervey Bay Dive Centre lists 'Hardys Artificial Reef' among its local dive sites. Each cluster forms a compact structure on sand with openings and overhangs that shelter cod, sweetlips and wobbegongs, while baitfish and trevally school above. Encrusting growth has built up on the concrete since deployment.

Its position close to K'gari means it is somewhat sheltered from south-easterly chop, but tidal current in this part of the Great Sandy Strait can be strong, so dives are timed for slack water. Visibility is typically low – 5 m or less – and fishing boats frequently sit on the marks.

The Hardie reef is a modest dive best suited to Open Water divers looking for a change from the older Roy Rufus structures. Keep dives to a single cluster, stay close to the modules in the low visibility, and watch for anglers' lines and anchors on the ascent. Being closer to the K'gari shoreline and the seagrass flats of the strait, the reef is also in an area where turtles and dugongs feed, and divers may see them on the run out. Dive it at slack water and plan the trip around the tide: the current in this part of the strait builds quickly once the tide turns.

Hervey Bay's boat dives leave from Urangan Boat Harbour (Great Sandy Straits Marina / Boat Club Marina, Buccaneer Drive, Urangan), at the eastern end of Hervey Bay's Esplanade about 10 minutes' drive from Pialba; there is free parking at the marina and a public boat ramp in the harbour. Hervey Bay Dive Centre runs its local wreck and reef trips from here. Hardie Artificial Reef lies about 2 nm north-east of Little Woody Island towards the K'gari shore near Bogimbah Creek – roughly 20-30 minutes from Urangan.

Published module marks include 25°17.277'S 153°01.492'E and 25°17.926'S 153°01.841'E. Anchor in sand up-current of a cluster.

Hervey Bay lies in the lee of K'gari, so ocean swell is rarely a problem; the limits are wind, tide and visibility. South-east trades over about 15-20 knots kick up a steep, short chop across the bay, and strong northerlies do the same in summer. Tides in the Great Sandy Strait run hard, so dives are timed for high-water slack – the Roy Rufus reef is dived only around high tide – and neap tides give the calmest water and best visibility.

Visibility is modest, typically 5 m and rarely above 10 m, and drops further after rain when the Mary River and creeks discharge into the bay (December-March). Winter (June-October) is generally calmer and clearer, and coincides with humpback whale season.

Anchor up-current of a module cluster, drop back onto it and tour the three modules at 12-16 m, then return to the anchor line. Dive at slack water on a neap tide.

Hervey Bay Dive Centre (Urangan Harbour) – 'Local Wreck Dives' trips to the Roy Rufus Artificial Reef and nearby sites (Goori, 3 Ships, K'gari, Iron Maria, Hardie and Simpson reefs, Snapper Grounds, Moon Ledge) on demand, timed to the high-tide slack; private boats also use the site.