A:
since with a pontoon it is about support not clearance like a regular boat trailer..
couple options for you, just cut a new piece of square tubing to the lenght you need to make it long and stiff use a heavier tubing, also if you don't go far and often, due what most due since the pontoon trailer are so high off the ground, put the motor all the way down, turn it all the way one way and use a rachet strap from the traler around the motor back to the trailer, all your trying to due is stop the motor from bouncing up and down and putting strain on the transom of the boat, just make sure your lower unit is still at least 18" or more off the ground and you are good to go.... done this hauling the potoon 120 miles each way twice every year......work great...