A boat that caught fire and sank near Nelson on Wednesday was an historic vessel that served in World War II.
The Auckland couple who lived on board had to escape in an inflatable life raft and were rescued by the Coastguard and a rescue helicopter.
Police say the owners of the 13-metre Tarapunga lost all their possessions when the boat went down near Pepin Island, north east of the city.
The Tarapunga was built in 1942 in the United States and served as a harbour defence launch both for the United States Navy and the New Zealand Navy.
It was also used extensively for survey work.
The boat was advertised for sale last year for $85,000.
The couple were treated at Nelson Hospital for smoke inhalation and one of their rescuers has offered them a place to stay
The Nelson Marlborough Rescue helicopter was despatched to the scene about 1pm, with the crew saying the vessel was well ablaze when they arrived.
St John Nelson Bays manager Matt Wilkinson says it was a lucky escape for the two survivors:
"We got a thumbs up from the people in the liferaft. They just indicated that there were two people and both of them were fine. We stayed with the boat until the Coastguard and a passing fishing vessel came to the scene."