John,
I was able to try mine out on a dumpster this weekend. The dumpster was to short for the MK, but showed me a long one will work-thinking this thing could be used as a dump truck.
I first tried with the hook coupled rigid with pin in place (no folding). That didn't work. I then pulled the hinge pin out to allow for hook to fold over. That worked well.
A long 20 footer should work-or perhaps an even longer one.
Perhaps the toughest part of this was removing the large X-member that was on the hook. It was a cluster to remove this thing. I had heard these things injured or killed troops when handling them. I can see how that happens-these things are poorly engineered to the MK18 operation. As a person with 30 years of designing engineered products that people interface with in the industrial sector, I could never let something like this out. My X-member is going to become a decoration for the side of my barn-good ridance to its operation.
Outside of that, the MK48-18 is a real workable combination. The hydraulic hinging of chassis allows the unit to get into places that might present a huge challenge for a regular truck. There is enough weight on the truck to keep off camber loading much more safe than a typical rig.
Pete