The J P Webb was a steam-powered hopper barge of 983 tons, built in England for the Melbourne Harbour Trust to work dredging spoil in Port Phillip. On her maiden delivery voyage in 1951 she was wrecked on a reef north-west of Ledge Point – the reef now bears her name – and never reached Victoria.

divingwawrecks describes the wreckage spread over about 40 m running north-south in about 4 m of water. The northern section holds scattered machinery, the large boiler and the triple-expansion steam engine, which make impressive snorkelling subjects in clear water. The reef around the wreck supports weed, sponges and fish such as buffalo bream, sweep, wrasse and herring, with crayfish in the reef ledges.

The site is better suited to snorkelling than scuba, and demands very calm conditions. It is a rewarding stop for private boat owners from Ledge Point on a glassy morning, and can be combined with the Key Biscayne oil rig wreck (a deeper dive 9 nautical miles offshore) or the Vergulde Draeck reef.

Practical notes: Ledge Point's beach ramp suits small trailer boats only in calm conditions; larger boats launch at Lancelin's boat ramp, about 15 minutes' drive north, adding a short run south. The reefs north-west of Ledge Point are shallow and unmarked in places, so navigate by chart and GPS and keep a lookout for breaking bombies. Because depth is only about 4 m, a snorkel with a mask, fins and a light wetsuit is all most visitors need. The boiler and engine are the largest pieces of wreckage and are easy to find first; the remaining plating and frames are scattered toward the south and partly overgrown by weed. Early mornings before the sea breeze give the clearest water, and the site pairs well with a deeper dive on the Key Biscayne oil rig 9 nautical miles further offshore on the same trip.

Ledge Point is about 125 km (1.5 hours) north of Perth. Launch at the Ledge Point beach ramp (or Lancelin boat ramp) and run about 2 nautical miles north-west to Webb Reef (10 minutes). divingwawrecks recommends anchoring well away from the GPS mark (S 31° 06.216', E 115° 20.271') because the wreck sits in breaking water, and swimming in.

The J P Webb lies on a reef in just a few metres of water, so it is only diveable in very low swell – divingwawrecks gives under 0.5 m. Any swell creates surge and breaking waves over the wreckage. Dive on calm mornings with easterly winds before the sea breeze.

Anchor well clear, snorkel in to the northern end and explore the boiler and triple-expansion engine, then follow the 40 m debris field south. Stay out of the break zone.

No operator – private boats; better suited to snorkelling.