As he endured his 15th hour floating off Leeman, the tattoo Kim Thomsen shares with his son reminded him why he had to stay alive.
In his first interview since a fishing trip with nephew Sean Coffey, 23, and Sean's mate Bryce Weppner, 24, turned into a tragic battle for survival, Mr Thomsen told how he clung to the hope the others had survived after they became separated.
The men had been reeling in pink snapper near Beagle Island when two big waves sank their 6m boat and flung them into the water on August 9 two years ago.
Mr Coffey, the best swimmer, made for Beagle Island about 500m away but was never found and Mr Weppner drowned after drifting away from Mr Thomsen.
After 19 hours battling fatigue and the elements, a naked Mr Thomsen was spotted from a Channel 7 helicopter. He was waving and praying for help as a hammerhead shark circled him.
Mr Thomsen, who for months afterwards awoke from nightmares, said he pushed himself until he had nothing.
"I was very alone and just had one thing to think about and that was my son," he told Channel 7's Today Tonight.
"We've got the same tattoo and every time I took a stroke I could see that.
"We both got 'you'll never walk alone'. We're Liverpool (soccer) fans. That sort of kept me going."
Mr Thomsen said he went into survival mode with Mr Weppner and they swam with the current until they drifted apart just before sunrise when he could not yell any more because his throat was raw from salt water.
"My back was aching because you are constantly just holding your head up," he said.
"You can't float because the waves are just that annoying size . . . that if you tried to just float on your back to have a rest, you'd get swamped. But what you really want to do is just put your feet down and stand up for a second - but there's nowhere to do that."
Mr Thomsen said he knew he was very lucky but did not want to be made a hero because their story was so tragic.
"It made it worse that Sean was never found," he said. "I've lived most of my life but those boys hadn't, so it's a bit unfair.
"Not a day goes by without me thinking of those boys."
Mr Coffey's mother Grace said holes in Leeman's radio network let the trio down because they were unable to tell authorities they were going fishing.
She wants mobile numbers for authorities to be more available and for sea rescue volunteers to get more support.
"This is pretty horrendous, especially when you're told later on that it could have been prevented," she said.