I wonder if the rear wheels are connected to the propeller and the front tires to the rudder.
I wonder what they have done to keep it from capsizing. That thing has got to be pretty top heavy. Maybe the bottom half of the boat is filled with cement.
Hard to tell but it looks like the right rear wheel is not mounted.
Either the rear driveshaft/axle has been connected to a drive system for the boat, or, the van body is just there as a cabin, and the van's entire drivetrain might be gone.
With a barge like this there are small gas or diesel industrial out-drive propulsion units like this,
which sit on the stern of a barge and work much like an outboard motor.
I could see a rig like this being placed on a "Low Boy" trailer and towed to the head waters of our
major rivers and taken on a slow leisurely trip down the river while stopping and driving the RV off
the barge to go touring on the land.
That looks a lot like an idea I had way back when. Put the front tires in a block that would turn the rudder when you turned the steering wheel and double rollers under the drive wheels that would turn the propeller. A set of outriggers to turn it into a towable trailer too. Never had the money or enough drive to make it happen though. There may be a market for it now.