Oxygen tank that was keeping youth alive took him under when his dinghy capsized.

Terminally ill Troylane Tetai didn't have much time left, and he wanted to use the little he had to fish. But his life came to an end sooner than anyone was expecting.

The 19-year-old drowned during a trip on his beloved dinghy off East Auckland on Saturday - pulled under the waves by his oxygen tank that he needed daily to live.

A friend survived only by clinging to the overturned hull for six hours.

About a week ago, Troylane, who has been battling bone cancer for five years, was discharged from hospital. The doctors said the end was near and he should be spending time with his loved ones.


His sister, Lenise Tetai, 26, said Saturday's blue skies were too hard for him to resist. "Pretty much all he wanted to do was fish."

Troylane made his way to Eastern Beach with his dinghy, oxygen tank in tow. About 4pm, he and his friend texted the people who were due to pick them up from the boat ramp. They were on schedule to meet.

But after 40 minutes of waiting - without any sign of them or the dinghy in the Tamaki Strait - the friends called the Coastguard.

"They hit some big swells coming back in and the boat capsized and they were thrown into the water," said Ms Tetai.

"His friend tried to save him. She swam over to him and took his oxygen tank off because it was weighing him down and in the struggle to keep him above the water, his lifejacket came off. She lost him and then when she found him again he was blue and lifeless."

Troylane's friend couldn't keep hold of him and he slipped beneath the waves again.

The 23-year-old friend clung to the overturned dinghy for six hours until the Coastguard found her, hyperthermic, exhausted and traumatised. She spent the night in hospital.

As word spread that Troylane was missing, his family gathered on the shore, scanning the horizon. They returned first thing yesterday, but all the searchers had found by last night was a backpack and an anchor.

"Hopefully he'll come home soon," Ms Tetai said.

She said their family was at peace with knowing they wouldn't see Troylane alive again. They knew he wouldn't be with them much longer, but they were struggling with how sudden and unexpected it was.

"He's gone out the way he would have wanted his story to end. He's in a better place, he'll be happier there."

Troylane, who grew up in Pakuranga but recently moved to Takanini, was diagnosed with bone cancer in his leg five years ago. He underwent gruelling treatment - and despite some patches of remission, the cancer spread.

Ms Tetai said her brother, the third of six siblings, was "an absolute trooper" when he was diagnosed and continued to fight hard, even as fluid filled his lungs.

"He used to say, 'They can keep taking it out of my lungs as long as they want'."

Troylane was extremely adventurous and loved fishing.

"He was also rebellious, the man with the plan and he was always doing something, hard to catch."

Senior Constable Steve Phillips of the police maritime unit said the Royal New Zealand Navy and police divers, using sonar equipment, would join the search today.