A chief accident investigator says the wreck of the fishing boat which sank off the Canterbury coast will be raised if necessary.
The Jubilee went down early on Sunday morning, and its three crew are still missing.
The crew believed to have been on board were Jared Reese Husband, 47, Paul Russell Bennett, 35, and Terry Donald Booth, 55.
A distress signal sent about 4.30am - when the boat was 20 kilometres from the mouth of the Rakaia River - indicated the crew members were heading for the boat's life raft. The raft was discovered by searchers later on Sunday but nobody was on board.
The Jubilee was located in about 40 metres of water on Sunday night.
Transport Accident Investigation Commission chief investigator Tim Burfoot said there were two investigators at the site of the wreck now.
He said getting divers down to find evidence was the main aim, as raising a vessel costs a lot of money.
"It really depends on what information we can get, if we can get the answers to this mystery without raising the wreck then we will do so, but if it comes to it and we have to raise the wreck to get those answers then we're prepared to do that."
Mr Burfoot said the company which owns the boat had been very helpful in providing initial information.
Navy to join search
The navy will join the search for three fishermen missing off the Canterbury coast.
Inspector Craig McKay said the navy's diving support vessel HMNZS Manawanui, will depart Devonport Naval Base tomorrow and make its way south to Canterbury where it will be met by members of their operational dive team and the police dive squad, when she arrives at the end of the week.
He said the navy's Remote Operated Vehicle would be used to confirm the identity of the item of interest located in 40 metres of water, near to the last known position of the Jubilee.
The Jubilee was built by Stark Bros in their Lyttelton ship building facility and first launched in 2008 by Ocean Fisheries Ltd. The 16-metre steel fishing trawler was worth more than $1 million when it was built.