By Leila Samodien & Murray Williams
The shark-watching vessel that capsized off Gansbaai over the weekend was hit by a "freak or rogue" wave, the NSRI has confirmed.
Two Americans and a Norwegian died after the wave hit the 11-metre catamaran broadside and overturned it on Sunday morning.
"Without a shadow of a doubt it was a freak or rogue wave," the NSRI's Craig Lambinon said on Monday morning.
Witnesses had differing estimates of the wave's size, but sources said it would have had to have been around four metres in order to capsize Shark Team.
Lambinon said the size of the average swell running on Sunday morning had been a relatively small and calm 2m.
Mariette Hopley, chairperson of the Great White Shark Protection Foundation, said the swell itself had passed beneath the boat, as a swell would usually have. But on top of the swell was a freak wave.
"It came down right on top of them," she said.
All 10 tourists on board and the nine crew members were thrown into the sea, and the three who drowned had apparently been trapped beneath the vessel.
Police spokesperson Andre Traut has named the drowned tourists as Cassey Scott Lajeunesse, 35, from Maine, Christopher Tollman, 34, from California, and Kenneth Roque, 37, from Moss, Norway.
After the tragedy, the vessel was towed to Gansbaai harbour, where it was righted using a large crane, and hauled from the water on its trailer.
The group of 10 foreign tourists and nine crew members were shark-cage diving in the waters off Kleinbaai, a small town next to Gansbaai, when disaster struck.
A Londoner - who was aboard the vessel but asked not to be named - said they had just finished diving and were preparing to return to shore when he saw the wave approaching rapidly.
"It looked like a freak wave, something like the wave on the video of the (2004 Indian Ocean) tsunami. The captain shouted for us to grab hold of something, which we did.
"I've never seen anything like it... it just makes you respect nature more."
While he escaped the ordeal unharmed, his wife, who suffered a fractured shoulder, was one of seven people who were injured.
Two people were taken to a hospital in Hermanus.
The witness, who was visiting South Africa for the first time, said he was impressed with the rescue efforts.
"I didn't have time to think, I just tried to get to the surface (of the water). Another boat was there to rescue us by the time I reached the surface," he said.
He explained that while they had been "rolling over" wave after wave, they had been unfortunate that this wave had broken on the boat, overturning it completely.
It is believed the three who died might have been sucked under the boat after it capsized.
An anguished Jeandre Horn, a friend of the Americans Lajeunesse and Tollman, said it had been the first time the two men had gone shark-cage diving.
Horn, from Johannesburg, and both men had been living with his aunt in Gansbaai.
He said he had worked with one of them at oil company Chevron in the US.
"I suppose the ones who survived were just lucky," he said.
Shark-cage diving operator White Shark Project, which deployed the catamaran, believed Shark Team was one of the safest boats in the industry.
While sea conditions were relatively rough on Sunday with strong winds and 2m swells, White Shark Project co-owner Charmaine Beukes said conditions had not been as volatile earlier in the morning.
She said the incident was "regrettable", but that rescuers had been "amazing" in getting the victims safely to shore.
Before rescue officials could reach the boat, the crews of other operators, who were in the water at the time, had rushed to the rescue of the passengers.
They had hauled the passengers aboard just minutes after Shark Team overturned.
Lambinon also commended the actions of local boats that rushed to assist those in peril.