I first saw this type of rig on the beach in St John USVI right in front of the beach bar.
A few years ago while visiting Spruce Island, we were picked up at the dock in Stonington, unloaded the car into sealegs and drove down the ramp into the sea to Spruce Island. A few days later we took the rig to Isle de haut (sp), drove up the ramp, parked in a parking lot and had lunch.
Pretty amazing.
pics/vid's later