Desperate boatie, 64, stripped naked and waved his board shorts at passing vessels as he clung to a beacon for dear life for three hours after being washed overboard

A boatie who was flung off his boat into the churning sea stripped naked and waved his board shorts in the air in a desperate bid to be rescued.

David Simpson, 64, was aboard his yacht MV Focus in waters off Caloundra, on Queensland's Sunshine Coast, on Tuesday when a violent storm swept over. 

As he rushed to tie down a dinghy, a massive wave smashed against the vessel and knocked him overboard.

A rescue operation was launched after the vessel was found at the northern tip of Bribie Island, off the coast of Caloundra, in the Sunshine Coast, about 4pm Tuesday with the engine running and no one on board

'The wave hit the side of the boat and I was trying to secure the dinghy which had come a little bit adrift and a rope broke holding the dinghy,' he told the Courier Mail. 

'The dinghy hit me, my ribs and I fell about 2.5, 3m off the boat.' 

Mr Simpson swam for 30 minutes against the tide to an ocean beacon as he watched his boat - and his beloved pet staffy Mitch who was still on board - rapidly drift away.

He said he wasn't afraid of drowning because the beacon was in sight- but he did hold fears about what creatures were lurking below. 

David Simpson, 64, was aboard his yacht M.V. Focus at Caloundra towards the northern tip of Bribie Island on Queensland Sunshine Coast on Tuesday

'I knew I could swim to it. I was more worried about sharks. I know that area's filthy with sharks,' he told the Sunshine Coast Daily.

After scrambling up the ladder, Mr Simpson took of his only item of clothing, a pair of boar shorts, and tried to flag down several boats.

'I was waving and jumping up and down,' he said.

'I took my board shorts off and was sitting there naked and jumping up and down waving my orange board shorts. That's all I had on.'

Despite the creative tactic, none of the vessels saw him, prompting Mr Simpson to come up with a new approach. 

As the afternoon light faded and the beacon's red warning light came on, he wrapped his arms around the globe every few minutes to create a flashing SOS-style signal.  

Mr Simpson managed to make it to a water beacon where he waited stranded for three hours before he was rescued

The unusual lighting caught the attention of a passing boat, who called the RACQ LifeFlight Rescue helicopter.

The helicopter flew to the beacon and hovered over Mr Simpson to keep a light on him, while waiting for the Coast Guard and police boats to arrive.

Mr Simpson was eventually brought aboard a police boat, ending his terrifying three-hour ordeal stuck at sea.

Authorities spent the afternoon and evening searching for Mr Simpson after his vessel was found abandoned after it ran aground on the northern tip of Bribie Island, south of Caloundra, about 4pm.

Lifeguards climbed onto the yacht and found a dog, the engine running, and no one on board sparking an urgent rescue operation.   

Mr Simpson, who lives on board the MV Focus, was reunited with his pooch Mitch on Wednesday afternoon after the dog had temporarily been taken into the care of lifeguard members.

Things took an unexpected turn and strong winds rocked his boat and he was flung overboard after a massive wave hit the vessel

He is still trying to determine how much damage had been done to his yacht, which is yet to be salvaged.

Crews had to abandon an effort to tow the stranded vessel to shore on Wednesday after the tow rope snapped and the boat filled with water.

A Coast Guard Mooloolaba spokesman said crews would now need to pump out the water the boat before it can be brought in, which would commence in better weather conditions.

Mooloolaba Coast Guard Ian Hunt said Mr Simpson was lucky to have made his way to the beacon.  

Mr Simpson said he was extremely grateful to everyone involved in his rescue, particularly the lifeguard who saved Mitch.