Abstract: A programmable logic controller (PLC) includes a central processing unit (CPU), at least one input/output (I/O) module and a communications interface between the CPU and the I/O module. The communications interface incorporates a universal serial bus (USB) protocol to create a standard, open interface providing a low cost, reliable communication link.

Abstract: A fresh water supply and waste water retention system is incorporated within a floating carrier for transporting land based recreational vehicles on a body of water. The system includes one or more fresh water containers and one or more waste water containers, all of which are symmetrically disposed about a selected lateral axis of the carrier. The system permits the transfer of water from the fresh water containers into the waste water containers without affecting the center of gravity of either the fresh water supply and waste water retention system or the center of gravity of the floating carrier/recreational vehicle combination.

Abstract: Method and apparatus for converting recreational vehicles (RVs), camper bodies and trailers from land-based units to water-based units. Following conversion, the RV or camper becomes the "cabin" of a houseboat having an undercarriage which includes a pair of catamaran floatation pontoons supporting a flat deck. The undercarriage is fully supported during the loading of the RV or camper and is positioned level with the loading dock regardless of the water level in the launching body of water. The RV or camper is adjustably positioned on the undercarriage to produce a positive angle of attack in which the stern draws a deeper draft than the bow, and is then secured to the undercarriage to prevent relative movement between the RV or camper and the undercarriage.