HMAS Karangi was a Kangaroo-class boom defence vessel operated by the Royal Australian Navy (RAN) during World War II.

[5] After the decommissioned Royal Netherlands Navy submarine HNLMS K XI sank in Fremantle Harbour, Karangi was used to raise the hulk as part of the salvage operation in early 1946.

[8] From 9 - 27 November of that year, Karangi embarked party of four British scientists and military officers at Onslow to conduct a detailed survey of the Montebello Islands.

[9][10] In February 1951, she was dispatched to assist the amphibious landing ship HMAS Labuan, which had broken down at sea while returning from the Antarctic carrying a scientific expedition.

One of those injured had been standing above decks and was struck by shrapnel receiving lacerations to his face when a skylight over the engine room shattered and was taken to the Repatriation General Hospital.

In preparation for the arrival of the British task force, Karangi and sister ship HMAS Koala laid moorings and marker buoys in the islands.

[15][17] Karangi continued to operate in Western Australian waters and around the Montebellos until September 1954, supporting WAPET's oil exploration activities on Barrow Island, still within the exclusion zone.

[9] As part of Task Group 308.2, Karangi remained in the Montebellos and was present near the naval base camp at Onslow, approx 140 km (87 mi) away, at the time of the second Mosaic detonation.

Formerly surrounded by industrial uses, redevelopment of the area, including the adjacent Sydney Olympic Park has seen renewed interest in the remains of Karangi and other vessels in the bay as a minor tourist attraction and popular location for photography.