Hot tubs are great, but they're usually stubbornly stuck in one spot. The HotTug is a seaworthy hot tub, for relaxation that's going places.
Made of fiberglass, the boat takes 480 gallons of water and is heated by a wood-burning stove. Being filled with water makes it pretty stable, even in the ocean. HotTug can be used unfilled, too, as a regular boat.
We first wrote about the HotTug in 2012, and since then, it's only become more available. You can now rent one in London, Rotterdam, Copenhagen, and Zürich, and as of last year, they're available for purchase in the US.