Police say the rescue of eight people, including four children, whose catamaran sank near North West Island off Gladstone, in central Queensland, could have been a "completely different story" had they not had life jackets and an activated EPIRB.
Queensland water police, a helicopter and a rescue jet had been searching for the group after the EPIRB was activated before 10:00am.
Authorities received reports an eight-metre vessel off the Capricorn Coast was taking on water and sinking.
"We're very grateful that for all the persons on board, they had a life jacket for each person and they had a current registered EPIRB," Senior Constable James Purbrick said.
He said a search-and-rescue operation was coordinated from Rockhampton and Canberra.
"The Capricorn helicopter rescue chopper was dispatched, as well as water police from Gladstone," he said.
"Those survivors were rescued from the boat onto a local marine vessel where they were medically cleared by the rescue chopper and transported back to Yeppoon Rosslyn Bay."
The aircraft were circling above the group as they were being rescued by sailors aboard the bulk carrier RTM Twarra, after the merchant vessel was diverted to the scene by the Australian Maritime Safety Authority (AMSA).
It is not known how or why the boat started taking on water and it is now fully submerged.
"AMSA wishes to thank the crew of the RTM Twarra for their help in this successful rescue," the organisation said in a statement.
