The pair were pulled from the water and onto the shore by off-duty lifeguards.
Attempts to resuscitate Lionel were unsuccessful, but Sam was taken to Taranaki Base Hospital.
The death has left a devastated family in mourning, with his four children unable to stop their tears, said Tristan.
"The kids have been crying all night and during the day today. It's been hard to just keep them going. [Lionel] loved his kids, he lived for his kids.''
One of eight boys and four girls, Lionel grew up in Gisborne. He spent much of his life in Hamilton, and moved to Waitara, north of New Plymouth several years ago for a ``fresh start'' after splitting with his wife.
Tony Reade supervised Lionel in his job as a fitter and turner in the Taranaki Engineering machine shop. His workmate had quickly became a valued friend, he said.
"Nothing was an issue. Nothing was a drama. He would give you the shirt off his back.''
Mr Reade had gathered with fellow workshop employees to remember the "man's man'' over a few drinks yesterday.
"Lionel had just got his life together. He was a solo dad, and brought his kids down with him. He'd set them all up in schools and everything, he was on a level playing field. And suddenly it's all gone.''
The family man was often seen out biking with his sons, kept himself fit playing tennis, and often swam at Fitzroy Beach.
Taranaki Engineers director Murray Dick said he was honoured to have known such a "true gentleman''.
It was not surprising Lionel had leapt to the aid of his son, but it was a shock that he was unable to negotiate the rip himself, he said.
"He didn't make bad decisions, and that to me was a bad decision but that was to save his son's life. It's really gut-wrenching.''
Memories of Lionel flowed yesterday from his many friends, all of whom said he would be sorely missed.
A handful of shocked friends gathered with Lionel's children and flatmate last night, some talking until 4am as they were unable to sleep after the news.
Esther Timu played tennis with him at the Waitara Tennis Club, and said the way he had died showed the man he was.
"It's reflective of how honourable he was. You couldn't get any better man than him.''
Lionel's extended family have gathered in Hamilton to farewell him.
He will spend two days with his ex-partner, and one with his sister, before being farewelled in a memorial service on Monday, said Tristan.
Since Christmas Eve, 11 people have drowned on beaches throughout the country.
East End Lifesaving Club development officer Andy Cronin said rips were common on Fitzroy Beach, and the lifeguards had to move the safety flags several times on Wednesday because dangerous currents kept changing position.
