An initial examination of the boat three men were fishing from before they drowned in Lake Tekapo has shown it collided with a submerged log.
The body of Alexander Haywood, 72, was recovered from the water on Thursday. His son Anthony Haywood, 46, and their friend Murray Green, 54, are missing, believed drowned.
The three men left Tekapo on Wednesday morning and when they failed to return by nightfall a family member began searching for them.
Their fishing boat was located by an Air Force helicopter at about 3.30am on Thursday near the Cass River, which flows into Lake Tekapo.
Senior Constable Brent Swanson says it is believed the impact of the boat hitting the log threw the men into the lake.
The boat, which still had power, headed off and ended up on a sand bar, he says. The men were unable to get back onto the boat or get to shore.
Senior Constable Swanson says none of the men were wearing lifejackets, though even if they had been, it may not have saved them.
The weather conditions were bad and they would have been in the extremely cold water for at least seven hours before they were reported missing.
Senior Constable Swanson says Tekapo has a reputation for not giving up its victims. The bodies of seven people remain in the 120-metre deep lake.
