Huddle

If you're ever invited to hang with Huddle cofounder and CEO Alastair Mitchell bring protective clothing, like a life vest, and maybe a fire extinguisher.

That's because when he's not running Huddle, a company that makes collaboration software that competes with Yammer, he's doing something daredevil (he'd call it "stupid"). Or he's building a car. Or a boat. And things don't always go as planned.

"To build something big you've got to start by knocking something down. That's been the guiding principal that I've had since I was a kid," he told Business Insider.

Thinking big came from his grandfather who in the mid-20th century built the biggest thing floating in the ocean, called the Ninian Central Platform, he says. It's an oil rig, the size of the Empire State Building, under water.

The thing was so massive that his grandfather had to buy a bay in Scotland to build it. He drained the bay, built the rig (on its side), refilled the bay with water and floated the rig out to the North Sea "where it lives to this day," Mitchell says.

His grandfather inspired Mitchell to become an engineer. But sometimes he goes a little "Top Gear" with his own projects. (We're referring to the British TV show about men and their sports cars.)

"I believe you need to make a difference with your work life and you need to experience everything you can outside of your work life. Occasionally that means doing some pretty stupid things," he says.

For instance, he took a lightweight Lotus car chassis and put an engine in it that was "dramatically bigger," he says. "Then you drive it and in my case, you blow it up. I've blown it up twice actually."

Yes, he literally set the rear end of it on fire.

He sent us this picture of him driving the car a few minutes before it blew up.

Alistair Mitchell

Huddle CEO Alastair Mitchell car

He collects other cars, too including a Caterham 7 kit car (that he built), a BMW M5 ("the biggest, fastest 4-seater, a crazy machine"), a Golf VW GTI and a Jeep Wrangler ("with huge wheels'), he says.

When not into fire, he's into flood.

He likes to sail his 18-foot skiff, the fastest kind of single boat, as fast as he can. Skiffs are flat-bottomed boats, meaning there's no big keel on their bottoms to counter-balance them. The faster you go, the more the boat will lean over and "I'll definitely capsize," he laughs. "If you want to go fast, you've got to blow something up."

He sent us this picture of him sailing on his boat being uncharacteristically mellow about it.

Alistair Mitchell

Huddle CEO Alastair Mitchell sailing

That "blow things up" attitude permeates Huddle, he says, and it seems to be working for him.