The D9 is the most complete wreck in Cockburn Sound: a 51 m steel dredge sitting upright and largely intact in about 12 m, rising around 5 m off the seabed. She was built in the 1930s as the bucket dredge Parmelia, later sold to Dredging Industries Australia, renamed D9 and converted to a suction dredge to maintain the Sound's shipping channels. She foundered in 1962 and was towed to the middle of the Sound and sunk. The bow faces the coast.

Because the hull is intact, it is a proper wreck dive at a shallow depth. Some compartments are still enclosed but full of silt, and the deck and superstructure provide ledges and holes for fish. Snapper, trevally, bullseyes and old wives school around the structure, stingrays rest on the sand beside it, and the steel is covered in sponges, ascidians and invertebrates with plenty of nudibranchs. Octopus, crabs and crayfish come out after dark, which makes it one of the better night dives in the area.

The Sound's fine silt is the main issue. Visibility can be good on a calm day but drops to nothing inside the wreck with one careless kick, so penetration needs wreck training and a line. The wreck is also a popular fishing mark, and lost line and abandoned rope are common.

The D9 suits Open Water divers looking for an intact wreck without the depth or exposure of offshore sites, and trained wreck divers who want an easy penetration practice site in shallow water. It is close enough to Rockingham and Woodman Point for a short morning outing.

The closest launch is the Naval Base boat ramp off Cockburn Road, which Divingwawrecks describes as in poor condition and suitable only for small boats in good weather; Woodman Point and the Rockingham ramps are the alternatives, 15–20 minutes away. Run west about 2 nautical miles from the Alcoa jetty to the GPS mark in the middle of the Sound. The wreck is also a popular fishing mark, so there may be boats anchored on it.

Cockburn Sound protects the D9 from ocean swell, so it can be dived when the coast is closed, but strong winds of any direction raise a short chop in the Sound. North-westerlies ahead of winter fronts and the strong summer south-westerly sea breeze both make anchoring uncomfortable; go in the morning or at night. Visibility ranges from 1 m to 10 m and falls after blows because of the Sound's fine silt.

Descend the shot to the deck at 7–8 m and circle the hull at 12–13 m, starting at the bow (facing the coast). Look into the open compartments from outside, then come up to the superstructure and deck machinery for the second half. Ascend on the line.

Penetration only with wreck training and a guideline; silt-out risk is high.

Visited occasionally by Perth dive schools and clubs, often as a night dive; mostly dived from private boats.