He was cold, exhausted and afraid.
But the German tourist's fears of being lost at sea amplified when the laser light fell from his grasp and disappeared into the dark water.
It was two more hours before the Christchurch-based Westpac Rescue Helicopter crew, scouring the sea with high-tech night vision goggles, found Mr Cartier, 19.
But it couldn't pluck him out of the choppy seas in the dark, with 20-knot north-nor'west winds.
Local fishing boat Navigator was radioed to pick him up 4km off the coast of Motunau, in North Canterbury.
"It was very nice to see them," the relieved engineering student from Bremen said yesterday [Monday].
After he was rescued about 10pm Sunday, Navigator skipper Geoff Basher gave him a "hot feed, cuppa, and a sleep" at his Motunau home.
Sitting in the Basher family kitchen yesterday, Mr Cartier told APNZ how his voyage went so wrong.
He had been driving around New Zealand with a mate since December, parting ways after arriving in the South Island.
"One morning I woke up and thought, 'Why don't I buy a kayak and paddle a bit of the South Island..."
Six weeks ago, the experienced kayaker set off from Kaiteriteri and spent a fortnight paddling around Marlborough Sounds.
He had a vague plan of negotiating the eastern coastline down to Bluff.
After stops for bad weather, he left Gore Bay at 10am on Sunday.
Mr Cartier estimated a voyage of seven hours to the popular fishing harbour of Motunau where he planned to camp overnight.
But as he approached the 3-hectare Motunau Island, 1.2km offshore, an underwater current started taking him out to sea.
He battled the flow without success.
"It was a bit scary. It was dark, I couldn't see anything. I was tired and cold," he said.
About 6.30pm, he activated his emergency locator beacon.
The Westpac Rescue Helicopter spent several hours trying to find him.
"I saw the helicopter a lot. I have a small red light for emergencies like that, but my fingers were so cold I didn't have any feelings in them and I dropped it in the water. I had nothing to show them where I was."
Rescuers say it was "extremely lucky" they found him.
Paramedics checked him out but he declined a hospital admission.
"I was just relieved to get out of the water. I was cold and afraid, so when Geoff invited me in, I was very thankful."
Mr Basher said the well-equipped and prepared kayaker was "pretty fortunate" to be spotted in such rough seas, but had been unlucky to strike the localised current.
After his ordeal, Mr Cartier is unsure whether he should continue paddling south.
He knows his goal of reaching Bluff as the winter weather patterns emerge is unrealistic.
And he's enjoyed his adventure so far.
"It's been a beautiful way to see an amazing place," he said.
"I've met a lot of people who have shown me great hospitality. But I have to think long and hard over whether I continue."
