While in La Paz, Homer, the property manager gave me these wheels and rigid floats to make a trailer. I added two ropes to keep the wheels straight without restraining their movement left and right.
Check where I attached the ropes. this is key. They have to be far ahead of the wheels.
I was able to pass over rocks, strairs and a quarter mile of sand. I’ve used it a dozen times.
This was done on the fly and it works ok. I hope to build one that will fit closer to the middle of the boat so I don’t have to do as much lifting. That said, the scupper pro is not very heavy. The wider improved version may have a harder time to stay straight.