"The weather had really turned on him."
Beausoleil said the waves were about 4m high and the wind was gusting between 80 and 120km/h.
After discussions with the sailor, it was decided he should jump into the water and be winched to safety from there.
"He wasn't able to make the boat steer in any particular direction," said Beausoleil, adding that it would be too dangerous to bring the helicopter close to the boat if it suddenly changed direction.
The sailor was in the water for less than a minute before being winched to safety.
"He was in the water by himself for about five to seven seconds."
The paramedic then spent about 30 or 40 seconds securing the man to a rescue strop.
It was a "really high winch" of about 35-40m, because the helicopter needed to stay clear of the "really big, angry seas".
His life was saved and he's gone home to his family.
"It would be a pretty bad day to be out there on a boat, to be honest."
The man was flown to Wellington in a stable condition for medical assessment.
Beausoleil said the rescue was a challenging one, but the team knew what Wellington weather was like and were prepared for it.
"It's exactly the sort of stuff we train so much for."
He said the sailor was well-prepared with floatation gear and a personal locator beacon, and he made the right decision when he abandoned the vessel.
"It was the sort of situation where it could have ended up being capsized."
Beausoleil said it was unfortunate the man had to abandon his boat, but "his life was saved and he's gone home to his family".