Steve Mogridge, along with two crew from Argentina and Chile, was helping the owner of the 13m-long Korora, a 63-year-old Auckland man, sail the yacht from Riverton, where he had bought it, to Auckland.
The three crew were friends of the owner.
The owner, who did not want to be named or interviewed, collapsed with chest pains, difficulty breathing and passing blood about 40km offshore north of Oamaru. A radio call for help was put out about 6.45pm.
After a paramedic treated the man, who had a heart operation some time ago, he was taken to Oamaru Hospital about midnight. He was recovering there yesterday.
Mr Mogridge, who was skippering the yacht, said they left Riverton on Friday and on Sunday about 10.30am came into Oamaru Harbour to refuel.
They left about 2pm and were sailing to Lyttelton, where they planned to leave the yacht and fly back to Auckland because the owner had not been feeling well. However, later in the day the owner's condition deteriorated.
''I heard him calling out 'Steve, Steve'.''
When he went into the cabin, he found the owner in considerable pain.
A call was put out on channel 65 and picked up by a person on a boat in Oamaru Harbour, who passed it to police. The yacht turned back to Oamaru.
North Otago Search and Rescue Waitaki co-ordinator Peter Muldrew said because of the type of yacht, the weather and darkness, it was decided to send a boat with a rescue crew and paramedics to meet it.
Mr Muldrew said the sick owner could not be shifted into a dinghy to be transferred, so the paramedic got on board to treat him while the yacht sailed back to Oamaru. It arrived about midnight and an ambulance was waiting. Mr Mogridge praised the paramedic who stayed with the sick man.
''I got the impression he was pretty worried [about the sick man], but he stayed calm and that helped a lot and kept our spirits up,'' he said.
The yacht stayed in Oamaru last night.
