The unexplained fire killed a local man, who has not been named, while boat owner John "Craka" Walker managed to escape the blaze but at the cost of severe burns to his face, arms and hands.
Countess was the second of Mr Walker's boats to be gutted by fire in the past four months, after Lafayette was razed in June.
The Lafayette fire was found not suspicious by police but Detective Inspector Scott Beard said the incident would be looked at and "taken into consideration in regard to the current investigation".
Monday night's blaze occurred about 9.30pm -- beside the charred remains of Mr Walker's previous boat on the mudflats at Ostend, among a string of mostly rundown and semi-abandoned houseboats.
Emergency services were alerted by local boatbuilder's apprentice Tom Foster-Christie.
The 18-year-old was on a neighbouring boat listening to his radio when he was startled by screams from Mr Walker and banging on his window.
"I heard some yelling and then Craka came and knocked on my window. He was badly burned all up his face and his arms and hands were just all black.
"He was saying '[my friend] is on the boat'. He was pretty well just repeating that. He looked disoriented and obviously distressed."
The tide was out and the boats were on the sand at the time.
Mr Foster-Christie jumped out of his window with a small fire extinguisher but quickly realised it would be useless.
It wasn't possible to get inside the burning boat, he said.
"The doors were open, fire and smoke were billowing out. You couldn't see anything."
Mr Walker collapsed on the beach where emergency workers poured water on his burns until a rescue helicopter arrived. He was conscious and screaming in pain, Mr Foster-Christie said.
Another boat owner, who didn't want to be named, said there had been a series of misdemeanours, vandalism and retaliation in the "live-aboard" community in recent years.
He cited reports of stolen equipment and threats between the wilder elements of the bay's boat community. Heavy drinking, swearing and fighting were common in the area, the man said. Just weeks before the fire that destroyed Lafayette in June, another man had attacked the Lafayette with an axe, smashing windows and hacking at the deck, the neighbour said.
"There have been about five or six boats that have been burned in the last five or six years," the man said.
"Craka's first boat was attacked by an axe-wielding person. There's a lot of things that have been going on."
He described Mr Walker as a likeable man.
"He's what you'd call a loveable rogue. He doesn't fight, he loves his nature and his cats. He's a vegetarian. He's not a bad dude."
Another local resident, who was too afraid to be identified in case of foul play, said locals were on edge yesterday because of recent aggression among some boaties.
"You see and hear a lot around that area with the boaties and I know the boaties have a bit of conflict with each other at times.
"Last time [Mr Walker] found his much-loved cats burned to death in a cuddle embrace under the floorboards.
"This time, someone has died," he said.
Some people on the island thought the first incident should have been investigated further, the resident said.
Mr Beard said police had been unable to speak to Mr Walker at Middlemore Hospital because of his injuries. "We're interviewing local residents, people who are living on the boats around where the boat was itself, and anybody who can assist over on the island," he said.
The scene examination and a post-mortem examination would help explain what had happened.
- By Sam Boyer and Morgan Tait of the New Zealand Herald
