Hewitt's mates want to learn from ordeal

It is unlikely that diver Robert Hewitt, who survived 75 hours in the sea off the Wellington coast, was swept as far north as Waikanae, a Government oceanographer says.

Mr Hewitt, who went missing during a diving expedition off Mana Island near Porirua on Sunday, thought winds and ocean currents swept him 27km north to Waikanae, before drawing him back to Mana.

But Steve Chiswell of the National Institute of Water and Atmospheric Research believes Mr Hewitt was disoriented and is unlikely to have left Porirua Harbour.

Dr Chiswell said that using a tidal model and wind-speed data, he calculated it was "extremely unlikely" Mr Hewitt was anywhere near Waikanae.

"The tides certainly won't do it and for the winds to do it, you would have to have a sustained wind speed of about 16 knots, a southerly," the oceanographer said.

"Then it would have to automatically turn around and blow again from the north."

Dr Chiswell said the winds in the area at the time were closer to 3 or 4 knots but would have been slightly stronger on the water. He told the Weekend Herald he believed there were two alternative scenarios.

The first was that Mr Hewitt was sucked into Porirua Harbour, which Dr Chiswell said was where he would have expected the tides and winds to have swept him.

The second was that Mr Hewitt was swept north to Paekakariki, about 16km. But Dr Chiswell said even that was further than he would have thought possible.

"Based on the oceanography, he would have been more likely not to go very far. The tides could take him five or so kilometres.

"But when I looked at the actual tides, they were going in the wrong direction. They should have been taking him south at the beginning, but he said he was in a rip going north."

Mr Hewitt has said that during his 75 hours in the water he was at times hallucinating.

"My guess is that he was just completely disoriented," Dr Chiswell said. "My feeling is that he was a lot closer to Mana Island than he thinks."

Mr Hewitt's diving buddies plan to sit him down with charts of the sea around Mana Island and the Kapiti Coast and find out what happened.

They have a lot of questions for when they celebrate the 38-year-old Navy diver's return to Palmerston North with a barbecue, some beers and lots of kina and crayfish.

Aaron Skinner, who was in charge of Sunday's recreational dive, told the Weekend Herald that he could not understand how Mr Hewitt had not been immediately found.

Mr Skinner said the eight divers, of which he was one, all went down in "buddy"pairs. Mr Hewitt and his buddy were the last to enter the water.

"They went down, got to the bottom and Rob's buddy had problems with his ears. Rob brought him up to the surface, checked he was OK, and then said he was heading off into shore, which was approximately 100 to 150m away and the depth was 15m of water.

"He had good equipment, heaps of air and he is a very, very experienced diver obviously.

"That's the last that was seen of him at that point."

Mr Skinner said he waited the appropriate time for Mr Hewitt to surface and then immediately raised the alarm.

"I just can't understand how we missed him because we did a huge search ourselves. We had other boats involved within half an hour; the helicopter was up within 40 minutes.

"So everything was put in place very quickly, including the Coast Guard, and they were doing big searches. The helicopter was searching south and north of Mana Island very, very quickly. What more can you say?"

Mr Skinner, who has been diving for 15 years, said his group of divers were despondent when Sunday's searches failed to find Mr Hewitt.

"He is a really nice guy, I just felt so bad. It was absolutely terrible what happened. It was a completely different trip coming home, I can tell you - very, very quiet."

Mr Skinner said the divers had been aware there were sometimes currents around Mana Island but there was little current when they dived on Sunday.

"All the other divers were popping up around the boat left, right and centre and they didn't get taken away anywhere. The area we were actually diving in was very safe. The conditions, the visibility, were perfect."

Mr Skinner said that when the police and Navy divers did not find Mr Hewitt on Tuesday there was little hope left of him being found alive.

"Then the dive team searched on the Wednesday and there he is. He pops up floating around in the ocean. It is absolutely amazing.

"I didn't know how strong his mental strength was, but he must have amazing mana and mental strength."

Mr Skinner said it was important that he sat down with Mr Hewitt to work out what had gone wrong so the same thing never happened again.

"I want to sit with him with a chart and say, 'This is where we were - I've got the latitude and longitude - this is where we searched. Where were you?'

"I want to put some timings in place and find out from my personal point of view as a skipper, and hopefully everyone else will learn from this too."