I will state up front, no pictures, but I will get some! Across the bay from me on the shore a gentleman is building a new 2 story houseboat. I was amazed at the spunk of this man to take this on.
He had pontoons and the deck built in Florida from his design. Each huge pontoon is divided into sections and has some kinda of valving. The boat is 20' x 70' and said to have a capacity of 88,000# of which he plans to use half or 44,000# cap.. It has a large front deck equipped with hydraulic ramps to load/unload a small car. For the cabin he used treated wood for the sole plate and regular studs and 2x6''s thereafter, I didn't see a water barrier but did not get close from the water. Power is provided with a single 115 outboard.
He plans on cruising with this. Trying for a high mpg. Stated that the pontoons would allow for higher mpg and better handling. He wanted a car so where ever he went he could pull up to the bank or a ramp and unload it so he could explore.
Next time I go to the lake I will drive around and take pictures.