I have two roswell tower racks on my boat. One has 3 prongs made to hold two wakeboards. The other only has two prongs (I am assuming for a kneeboard). I'm trying to come up with ideas to make the opening smaller on the two prong rack as I have lost boards out of that rack in rough water.

I have thought of just using foam tubing around the prongs to make it a little smaller, but wondering if anyone has good ideas that may look a little cleaner?