The father of Scott Watson has ruled out a connection between a ketch scuttled in Gisborne and the murders of Ben Smart and Olivia Hope.
But Chris Watson says there are further questions that should be asked of the movements of a convicted drug smuggler who later bought the ketch, and who was thought to be in the Marlborough Sounds 10 years ago.
The yacht, which was scuttled in Gisborne Harbour in 2000, has been linked to the disappearance of Ben and Olivia by those who believe Scott Watson is innocent of their murders.
Witnesses to the last sighting of the pair gave descriptions of them boarding a "distinctive class ketch, with two masts, about 12-13m, with a white and blue hull with round portholes".
Since then, Watson's supporters and those who doubted the police case have called for sightings of the "mystery ketch", which the prosecution said didn't exist.
Rob Campbell, the salvage skipper who raised the yacht, told the Herald on Sunday he was convinced it was the "mystery ketch".
Campbell, of Bay Underwater Service, said he raised the yacht from where she was "deliberately sunk" in Gisborne Harbour in 2000. It was eventually scuttled 12km from Gisborne, in about 30m of water, well away from harbour traffic.
Campbell said he was astounded at the similarities between the yacht and the description of the mystery ketch, of which he had seen "identikit" pictures.
"There were 14 similarities between it and what they were looking for. We approached the police and they didn't want a bar of it."
He said similarities included the bowsprit, a tubular enclosure near the wheel, the same number and style of portholes and the blue stripe painted down the side.
"They [police] had their man and they didn't want to go looking in any other direction."
Campbell said he believed police had gone after the wrong man.
"I believe Scott Watson is 100 per cent innocent. I believe he's a bit of an odd character, but I don't think he did it."
Despite the boat being moored at Punga Cove, near Picton, on New Year's Eve, 1997 - the night that Ben and Olivia went missing - there was no chance that it was the mystery ketch, said Chris Watson.
It was too long, for starters.
Watson did, however, have his own questions about the movements of a man who later came to own the ketch.
That man is now serving a life sentence in an Australian prison for cocaine smuggling.
Watson said there were questions about whether police inquiries focused enough on the man's movements.
It was thought he and his associates were in Picton around the time of Ben and Olivia's disappearance.
The man has been linked to the ownership of numerous ketches and bought this one in March 1998.
"It's a boat of choice," said Watson.
Chris Watson said the man was known to be in the Marlborough area before March 1998, when he had told police he was there to buy the ketch.
"Police never interviewed him until September 1998 and then only once over lightly."
The interview sheet, which Chris Watson sent to the Herald on Sunday, shows a one-page record of a conversation with the man, focused entirely on the period from March 1998.