A third man managed to swim to a rock ledge after the tinnie was swamped and split in half on the rocks in storm-generated surf.

Westpac rescue helicopter crewman reaches the survivor on the rocks before he is winched to safety. Picture: courtesy of Channel Nine Source: Channel 9

Witnesses saw the men thrashing around in the water and called triple-0. The Westpac Lifesaver Rescue Helicopter was on the scene within three minutes. “It was around 1pm and our understanding is that a small boat, a tinnie with three people on board, was hit by a wave and overturned, throwing the three people into the water,” said Westpac Lifesaver Rescue Helicopter CEO Stephen Leahy.

Westpac rescue helicopter crew winch a man to safety after the boat he was on capsized in Botany Bay. Two others died at the scene. Picture: courtesy of Channel Nine Source: Channel 9

The boat was on the ocean side of Kurnell at the southern end of Botany Bay at Cape Bailey.

The rescue helicopter flown the man who swam to the rocks to Sutherland Shire Hospital, where he was treated for minor injuries.

“The Westpac Lifesaver Rescue Helicopter located the other two men floating face-down in the water. Both of the men were winched aboard the helicopter,” Mr Leahy said. The men were later pronounced dead.

Westpac crew winch a man to safety after the boat he was on capsized in Botany Bay. He was the only survivor of three men on the boat. Picture: Courtesy of Channel Nine Source: Channel 9

A spokeswoman for Surf Lifesaving NSW said: “None of the people on board the boat were wearing life jackets, and it was not the place to be in a small vessel without a life jacket.”

The rescue effort was co-ordinated by Surf Lifesaving NSW, which sent inflatable rescue boats from Cronulla Surf Club to assist.

The Westpac helicopter was also scrambled to Whale Beach on the northern beaches yesterday afternoon after a man was reported as failing to surface after being knocked over by a wave. He was later found alive.