The Pontoonz Modular Float System is an innovative creation from New Zealand that consists of 1.2-meter (about 4-foot) pontoon “pods” with built-in grooves where connecting beams can be bolted. The pods can be securely locked together in any number and covered with decking. The system is useful for making docks, floating platforms, and (with a special bow pod) small boats. As suggested by the small cedar-sided cottage on a 26-foot platform that Pontoonz completed in March of 2013, that could include tiny house boats. A really livable boat would probably require a somewhat wider platform, but given the scalability of the Pontoonz system it should be just a matter of figuring out how many pods you need.
h/t Tiny House Talk
Sure, a house boat isn’t for everyone, but maybe you want a special place to retreat on the weekend so you can float away from it all. Instead of pontoons you could use large steel drums, or even big pieces of styrofoam, though being in the water for a long time would probably put a lot of wear and tear on those materials. Regardless, it’s an interesting idea that shows how building a tiny living space on water can be as easy as building one on wheels, maybe easier. Of course, the company is based in New Zealand, which makes it unlikely anyone in the US or Canada will be able to take advantage of their plans, but there are similar resources easily found stateside, like pontoons for instance, which can be sourced on Ebay.