"Hang onto your drinks!" yells Sandy Williamson as he powers up the 30-foot pontoon boat.
Though it is below freezing, four of the six passengers are warm as can be because they are lounging in the hot tub...on the middle of the boat.
Water from the tub splashes onto the deck at takeoff.
"The concept of being able to do that with the scenery changing is pretty dramatic," says Sandy.
He's made pontoon boats for years with his company PontoonWest. But his latest idea combines two of life's greatest pleasure, boating and hot-tubbin'.
"It's even more pleasant if you're out on the water."
Sandy saw the smaller hot-tub boats for rent on Lake Union and thought he could do even better.
"I think this is just a much better application. A pontoon boat, it's stable, lots of room for people."
He just delivered the first hot-tub boat to a client in California. It features a 70-inch TV mounted on the front. That one sold for $50,000. But he can add or subtract to customize for just about anything a hot-tub boater's heart would desire.
"So it's just a question of how big's the hot tub? Engineering. How much does it weigh? Where's it gonna go? How big the pontoons have to be?"
And Sandy himself will soon be a client.
"After spending these few days with it, I'm doin' one for me!"