The Gemini is the north-metro coast's main purpose-sunk wreck and, according to divingwawrecks, arguably the most exciting dive off the northern suburbs. She was the hopper barge WH-301, built in 1962 and paired with her sister WH-302 in New South Wales. She later came to Western Australia and was bought by charter operator John Clark, and on 9 September 1993, with help from the Royal Australian Navy and local businesses, she was scuttled as a dive and training site for Advanced divers.

The 36.5 m, 860-ton steel barge capsized as she sank and lies upside down on sand in 30 m, on an east–west axis with the bow facing seaward. The top of the upturned hull is at about 26 m. Commercial divers later removed sections of the hull to allow penetration into the silt-filled internal spaces.

The wreck is a magnet for fish. Samson fish school around it, which also attracts anglers, and kingfish, old wives and truncate coralfish are common. Crayfish hide under the gunwales, and soft corals and sponges cover the steel.

It is a deep, exposed dive that suits Advanced divers with deep experience. Currents can be strong, it is not always easy to locate, and no-decompression times are short. On a calm day with clear blue water it is one of the best wreck dives in the Perth area. Spearfishing is not permitted on the wreck, according to the Marine Life Network.

Water temperatures on this coast range from about 17–18 °C in late winter to 22–23 °C in late summer; a 7 mm wetsuit with a hood suits most of the year.

Launch at the Mindarie Marina public ramp (Mindarie Keys, off Marmion Avenue, about 40 minutes from the Perth CBD). Run 8.4 nautical miles north-west to S 31°37.142' E 115°33.626', about 25–30 minutes in a trailer boat. The Marine Life Network notes that it can be hard to find by GPS, so use a sounder.

Drop a shot beside the hull rather than anchoring into it. Divingwawrecks lists Western Blue Dive Charters as having run the only local charter from Mindarie; check which operators currently visit.

The north-metro offshore sites face the open Indian Ocean with no island shelter. Swell comes mainly from the south-west and west, and the summer south-westerly sea breeze usually arrives late morning to early afternoon, making the run home rough. The Gemini is divable in light winds and swell under about 1.5 m.

It is subject to strong current at times, so check on arrival and dive at slack periods if possible. Visibility is often excellent, 10–30 m. Winter fronts bring north-westerly gales and big swell.

Descend the shot to the upturned hull at about 26 m, circle it on the sand at 30 m and look into the openings cut in the upper (now lower) side. Keep bottom time within no-decompression limits on nitrox, then ascend the shot with a safety stop.

Nitrox 28–32% recommended to extend bottom time; interior penetration requires wreck training, lines and silt-management skills.

Occasional charters by Perth operators and clubs for Advanced and deep training; divingwawrecks names Western Blue Dive Charters (Mindarie) as the historic local operator – currency unconfirmed. Also private boats.