The vessel found on the seabed near the entrance to Picton Harbour is not the yacht Sioux and is instead a much older boat, police say.
The vessel on the sea floor was [http://www.radionz.co.nz/news/regional/288865/mystery-wreck-found-in-marlborough
spotted during a naval exercise] and images were passed on to the police yesterday.
Police initially said it might be the yacht Sioux, which broke free from its mooring in a winter storm in 2010.
However, a Tasman Bays police spokesperson today said the Police Dive Squad had inspected the vessel and confirmed it was neither a yacht nor a ketch.
A further dive would take place tomorrow to gather more information but because of the depth of the vessel, divers had limited time in the water.
Officers were continuing to make inquiries to identify any other vessel which had gone missing in the area.
Detective Kris Payne yesterday said it would be far-fetched to connect the find to the 18-year-old disappearance of Ben Smart and Olivia Hope; witnesses at the time reported seeing the pair boarding a wooden ketch in the Marlborough Sounds but no such vessel was ever found.