Bluff man Jason Ross Nilsen is dead and his crewmate seriously injured after the pleasure boat they were in hit rocks late at night in a remote part of Doubtful Sound.

The injured men drifted in the damaged boat for an estimated nine hours before being spotted at 8.45am yesterday by a passing Department of Conservation vessel.

The accident was thought to have happened when the 6m aluminium boat hit rocks close to the shore at the Southern tip of Secretary Island late on Sunday night or early yesterday morning, Te Anau police said.

The boat was discovered by the crew of the DOC vessel Southern Winds drifting not far from the island, with Mr Nilsen and the injured man still inside.

Southern Lakes Helicopters rescue pilot Chris Green said the relatively new boat was extensively damaged below the waterline from where it had hit rocks. The steering wheel had snapped off and the propeller was damaged.

“It is a testament to the boat because if it had sunk, it would have been much worse for the (survivor). He would have been well and truly unconscious,” Mr Green said.

He estimated the cruising speed of that type of boat to be about 55-65kmh.

The second man was in a serious condition with severe head injuries, including a fractured skull and facial injuries. He was initially flown to Southland Hospital before being transferred to Dunedin Hospital yesterday afternoon.

Mr Green said the injured man was talking to rescuers when they arrived but was “badly broken up” and probably did not know what was going on.

Sergeant Tod Hollebon, of Te Anau, said it was thought the accident happened some time between 11pm on Sunday and early yesterday morning.

Mr Green said “scoring” marks consistent with an aluminium hull hitting rocks was found “by coincidence” on the east side of Blanket Bay, near where the boat was found drifting.

“It looks like, in the darkness, he has turned too soon,” Mr Green said.

The injured man was flown from the scene and a second helicopter was used to take police to the scene and to assist with the recovery.

Mr Nilsen, 33, was a commercial cray fisherman but was in a recreational boat and not working when the accident happened.

Mr Hollebon said the full circumstances of the accident were under investigation and the southern coroner had also been advised.

“It is not yet clear exactly what has led to the vessel floating in the manner it was found.”

Maritime NZ confirmed it would make preliminary inquiries before deciding if a full investigation was necessary.

Story by DAN HUTCHINSON, The Southland Times