Lack of boat and debris challenges police theory, fishermen's families tell inquest.
The families of two fishermen who drowned at Lake Arapuni say they may never know how their loved ones came to grief.
And at an inquest yesterday into the deaths of James Roberts and Jordan Pooley, family members voiced their own theory, which challenged what police believe happened on the afternoon of August 28, 2011.
But all agree the case remains a mystery that may never be solved.
Mr Roberts, 45, and Mr Pooley, 21, had set off from Jones Landing near Putaruru in a 3m-boat at midday, but never returned home.
The alarm was raised when Mr Roberts' border collie, Maggie, made a 10km trek home and was seen by a neighbour.
The men's bodies, life jackets and Mr Roberts' boots were eventually discovered after an exhaustive two-week search of the 25km-long lake, but neither the boat nor any debris have been found.
Both men had alcohol in their systems at the time of their deaths and were wearing heavy clothing but had not put on the life jackets.
Constable Jason Shailer of Putaruru told the inquest it was most likely the boat had struck one or more submerged trees in the lake and sunk immediately.
Both men would have been thrown into the water, which was just 11C at the time, and with heavy clothing, no lifejackets and inebriated, would have drowned quickly.
Mr Shailer said the boat was likely to have sunk and become caught up in thick weed growing in the lake.
Sonar searches had failed to locate it, but the technology could not penetrate the weed and it was "highly likely" the boat might never be discovered.
But Mr Pooley's parents, Helen and David, have questioned why no remnants of the boat or anything in it has ever surfaced.
The family had also received reports of the boat being loaded on to a trailer at the landing and towed away.
Mr Pooley believes the pair may have been fishing on the lake bank they travelled to by boat, before the vessel "got away from them" and both entered the water - perhaps one going in to rescue the other.
A friend of the Pooleys brought expensive sonar equipment from overseas to locate the boat, but several sweeps of the lake failed to find it.
"Things float - we found nothing," Mrs Pooley said. "And I think even our farming friends who live out there, they can't even understand why we've literally found nothing."
A regional harbour master said he had recovered hundreds of boats. That was the only one never retrieved.
Senior Constable Barry Shepherd called the case an "absolute mystery".
"It was interesting that we found the boots and vests, and it is a mystery to this day why we have not found a skerrick of debris from that boat."
Mrs Pooley said what happened to the boat was an unanswered question her family would have to live with for the rest of their lives.