"You just focus on exactly what you want to do," Hamilton-based Brown said.
"On that particular one there was a rock I just wanted to go to the left of." Brown and his mate were traversing a waterfall called the Drowning Drop in Iceland.
Since that mission, the two kayakers, both in their early 30s, have had adventures closer to home.
Their Flow Hunters exploits saw them kayak across New Zealand for the best part of 35 days. In that mission last summer the kayakers covered 8000km and took on 17 rivers.
The adventure was made into a TV show now on Sky Sports.
Brown said the remoteness of the South Island's rugged West Coast presented special challenges. "You've got to access the majority of the rivers by helicopter, which throws a whole other variable into the mix."
Adventures in more exotic locales have also featured since the Drowning Drop. Brown and Meehan were among a group of adventurers who tackled the wild rapids of Africa's lower Congo River.
The Grand Inga Project, also known as Congo 2012, was led by South African kayaker Steve Fisher and made into a movie set for release in August.
Brown often goes kayaking with Meehan, who said a cool head was needed to keep from going under.
"You don't really have time to think about anything else, apart from finishing off what you started and getting the hell out of there, really. The real feelings happen at the bottom when you look back up and see the waterfall," said Meehan.
Despite all the adventures since the Drowning Drop, Brown has some strong memories of that day in Iceland.
He had broken his back while travelling in Thailand just a year before he tackled the Icelandic beast.
"I landed quite hard, but it was all good," he said.
Here, they rate South Island's West Coast and the Kaimai ranges near Tauranga as top kayaking spots.
For those wanting to emulate their jaw-dropping feats, they have some advice: "Link up with a good school and get your skills up.
"You don't have to be plunging off massive waterfalls to make it fun."