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The man and three children winched off a boat off the Bay of Plenty coast this afternoon seemed in a remarkably good state considering their ordeal, their rescue pilot said.

While boat owner Rua Toe Toe stayed with the craft as it was towed to Tauranga by the Coastguard, Billy Mackie and the three children -- Henare Gardiner, Kamete Toe Toe and Janie Mackie, aged in the early to mid teens -- were winched on to the Northland Emergency Services Trust helicopter and taken to Tauranga airport.

Their boat, Wait N Sea, had been reported missing late yesterday morning.

A major search was launched and the runabout was spotted shortly after 1pm today, by the TECT rescue helicopter from Tauranga 5km west of Motiti Island, about 15km north of Tauranga and 13km from Maketu, from where they had set off yesterday morning on a snorkelling trip to Motonau Island, also known as Plate Island.

They had got lost in appalling conditions and poor visibility, which also hampered the rescue effort yesterday afternoon.

"They were showing no sign of seasickness, which surprised us, because they certainly had been rocking around out there," said the pilot of the Northland trust's Sikorsky S76 helicopter, Pete Turnbull.

"They said they had been a bit sick at times, but their spirits were good and they had not panicked and stayed with the boat."

While there was no emergency need for the four to be winched from the boat, "we were there, so to save them any further discomfort they were winched ashore," Mr Turnbull told NZPA.

"There were no safety issues involved, but they had been out in the boat a long time and it looked a pretty rough ride they were having."

Back at Tauranga airport, the four spoke briefly to media before being taken for medical checks and being reunited with family members.

Mr Turnbull's helicopter had been searching from White Island to Kowhai Point when the Tauranga craft located the runabout.

Tauranga police said the search had been an excellent success, with the Rescue Coordination Centre New Zealand taking control last night because of the size of the search area and the need for assistance from the air force.

An air force Orion had searched for the boat last night.

Mr Turnbull said it was a good example of having a "dedicated professional coordinator" in RCCNZ having an overview and allocating rescue helicopters, fixed wing aircraft and rescue boats to specific areas and tasks.

Rescue Coordination Centre mission controller Tracy Brickles said the rescue team was delighted with the successful outcome and wished to thank all those who were involved, particularly the large number of volunteers who had taken part in the search.

"Police, Coastguard, Surf Lifesaving, the air force and several rescue air services worked together to achieve a great result," she said.

The rescue highlighted the importance of boaties carrying reliable communications equipment, such as marine VHF radios, emergency beacons and flares.

A family member received a text message from the craft about 11.30am yesterday asking for the Coastguard to be called because the vessel was lost.

Rough seas and poor visibility hampered search efforts and an overnight search by the Orion using radar and other specialised search equipment over a 540sq km area failed to find any sign of the group.

At 6am today a second text, understood to say "Lost at sea", woke up Mr Toe Toe's wife.

Mihi Fraser, aunt to the children and Mr Mackie's sister, said before the boat was found it was the most trying time of her life.

"I can't bear the wait," she said.

She had been busy co-ordinating the scones and tea effort at the search headquarters.

Overnight, family and friends of the missing boaties had converged on the small Maketu Surf Life Saving Club.

About 40 people had crammed into the clubrooms, and there was "a massive sense of relief" when news of the second text message arrived, club chairman Mike Hickson told the stuff website "and everyone ran out on to the balcony to look out to sea".