It was low tide with moderate surf, the water was cold, and conditions were described as "a bit scary'' that night, the report said.
Dean Jolly was at the beach with his wife and children, when he was told there were two people in trouble in the surf. He saw the pair quickly dragged by a rip from about 10 metres offshore to between 30 and 60m out.
He and Lester White grabbed a boogie board each and paddled out to help. When Mr Jolly reached the son, he was "screaming that he needed help and that his dad needed help.''
While Mr Jolly battled the rip pulling him around, he grabbed the 10-year-old and put him on the board. Mr White paddled over to the father, who was found face down in the water not moving.
Two surfers, John Garcia and Mervin Farquhar, left a board riders' club beach barbecue to paddle out to help after hearing yelling and shouting on the beach.
Off-duty lifesaving guards helped pull the pair back to shore, and gave Mr Ogilvy CPR. Police then attempted revival with a defibrillator.
Mr Ogilvy was pronounced dead at about 7.30pm, which was about half an hour after it was noticed he and his son were in trouble.
Coroner Tim Scott passed the report on to the Royal Humane Society of New Zealand, and commended all four members of the public involved in the incident for their bravery.
Taranaki Engineering workmates were still "shocked'' by the death of their colleague, who worked as a fitter and turner for the company, said director Murray Dick.
Brother Tristan Ogilvy said that Lionel's children, three sons and one daughter, were coping with his death. All four were living with his ex-wife Angela in Hamilton, and were all "alright''.
Sam, 10, who was with his father when he drowned, was moving on from the death.
"I think he's okay, he's a fairly resilient boy. But it hasn't knocked him around too much, thank goodness.''
He had swum again, despite losing his father while in the water, he said.
Courtney, 18, was "knocked around'' after her dad's passing and was the most affected by the death, he said: "But she seems to be getting past it.''
Lionel has joined his father, sister and brother who are buried at the Newstead cemetery in Hamilton.