The 28-year-old Kiwi, nicknamed Rhino because of his bulk and power, is an Olympic cyclist who won track bronze at London 2012 and boasts three World Championship medals.
But he has switched the velodrome for a cutting-edge America's Cup boat, traveling at the same kind of 80 kph speed he tapped out on two wheels.
"I never dreamed I'd be going 40 knots in the air," van Velthooven told CNN from the last America's Cup
runners-up's Bermuda base ahead of the 2017 edition getting under way.
His team have left no stone unturned in the battle to lift the Auld Mug, sport's oldest trophy.
And in boats powered usually by human hand -- grinders turning manual winches -- New Zealand is generating its power with four bikes on board.
And who better to power them than an Olympic track cyclist?
Van Velthooven was first approached early in 2016 about the possibility of getting involved.
"Well, I'd been trying for the London World Championships in 2016," he says, "but the bosses decided they needed to take some new faces.
"So Team New Zealand came calling, and they were very serious about putting bikes on the boat
. They wanted to see if I could power that and it went pretty well."
But after that initial foray, he returned to the track only to miss out on selection for the Rio Olympics, or as he puts it, "the same old bulls***. My legs were good but they decided to take a younger rider for the future."
So the America's Cup came calling again, and van Velthooven became fully immersed in the project -- although he was unable to speak about it until February of this year when the boat and its pedal power was unveiled.
'A hell of a lot of fun'
Van Velthooven insists the pedal power is not necessarily the "silver bullet" that will give him and his fellow crew members America's Cup victory.
But it is one part of making the team fast and confident of wresting back the trophy from Oracle Team USA.
Growing up in New Zealand, he was aware of the America's Cup before he discovered track cycling -- mainly down to the national fervor whipped up by the first of Team New Zealand's back-to-back America's Cups in 1995 when he was just six years old.
But with a background of a few outings on his uncle's boat and an outward bound course growing up, he is almost certainly the least experienced sailor in the fleet for the 35th America's Cup.
Not that he is unduly concerned.
"The speed's very similar, and I'm still pedaling, the only difference is I'm now outside," he says. "This is still sport and still a winning culture.
"What's different is that before I was very much doing it more by myself, this is obviously more of a team now."
Van Velthooven is determined to prove that cycling's loss is sailing's gain and, while he has been on something of a crash course in his new found sport, thankfully that has yet to mean going overboard.
Tellingly, he speaks about himself as an athlete rather than a sailor -- a nod to his inexperience but also a change in the roles of America's Cup sailors on boats brimming with technology.
"I'm an athlete on the boat and I do as I'm told and then hold on dearly!" he adds, more in jest than reality, the Kiwi having to be nimble on his feet switching from one side of the boat to the other with haste.
"It's a lot more work and a lot more preparation but it's a hell of a lot of fun."
Initially he was dipping his toe in the water so the team's hierarchy could see what he was capable of, and more broadly what pedal power could achieve.
Then he was brought in to help coach the other "cyclists" on board before gradually earning his spot as one of the six pedalers that will take turns powering Emirates Team New Zealand.
And unsurprisingly, he is convinced pedal power is the way forward.
"Well," he says, "the legs are a bigger muscle group and they can generate more power."
Van Velthooven is used to an expectant nation looking on at his sporting achievements but he says the America's Cup in New Zealand is a level up from the Olympics.
"It was huge when New Zealand first won it and last time was a massive blow to the team and the country
," he says. "I want to be part of the team to bring the America's Cup back home, and we're confident we've got the speed.