Alan Saunders had promised to take his 11-year-old grand-son on a fishing charter as a birthday treat.
So come Saturday both of them were "incredibly excited" they headed out to Kaipara Harbour for a day on the water.
But, what should have been a perfect day out ended in tragedy when Saunders fell overboard and died soon after.
The 76-year-old's family are now grieving the loss of a devoted father and grandfather and questioning why the charter boat headed out in such stormy conditions.
Speaking on behalf of Alan George Saunders' family, stepdaughter Melanie Bridge said the trip was a long-awaited birthday treat for her son Spike Jackson.
Saunders was with Jackson when he fell from the commercial fishing vessel, Kaipara Kat Fishing Charter, about 10.30am. Emergency services were called to Shelly Beach Head, about 19km north of Parakai.
Saunders fel overboard while in the Kaipara Harbour, but was pulled back on to the boat, a coastguard spokeswoman said. He suffered a medical event once back on board the vessel, she said.
Bridge said Saunders was an enthusiastic fisherman, and a dedicated grand-dad.
"He'd been promising to take his 11-year-old grand-son Spike Jackson on a fishing charter as a birthday treat. [Saturday] was the day and they were both incredibly excited," she said.
"The boat headed out on the Kaipara Harbour in the early hours of the morning. The weather was bad, with high winds, and sea so rough that Spike and another child on board were vomiting."
Bridge said the family believed Saunders drowned after losing his balance in heavy seas and falling overboard with no jacket on. By the time his body was recovered and CPR was administered it was too late.
"Our family can not make sense of this tragedy. Alan was a smart and sensible man, how could this happen to him? Why did the fishing excursion go ahead despite the stormy conditions? Why wasn't everyone wearing lifejackets given the stormy conditions?"
Saunders was a beloved father, grandfather, partner and treasured friend, and she said he died "in an unbelievable fishing boat tragedy".
"Alan was absolutely one in a million. He was adored by all his family and friends and to say he will be missed is an understatement. Spike is being cared for by his family with guidance from victim support."
A spokeswoman for the charter company referred questions to the police.
Police are investigating on behalf of the coroner, and Maritime New Zealand is also investigating.
Maritime New Zealand spokesman Vince Cholewa said its investigators were due to receive a report from police tomorrow before deciding whether to take any action.