The P19 trap adjustment is NOT adjustable on the fly. It's a simple wrap-around rope lock that stops on the dogbone.

'ufcsailor19' - You have one of two options: Keep the existing stock system and before leaving the beach, both you and your crew go out on the wire on both sides. Adjust the length of the trap lines on the rope lock so that you're in line with the trampoline and crossbars. You can also use some electrical tape around the lines on the plastic blocks so that the length of the line doesn't slip. Or you can purchase a trapeze length adjustor (hi-lo) such as: http://store.catsailor.com/pc/viewPrd.asp?idcategory=351&idproduct=11792

I have the stock system and the rear ones are set for my personal height. The front ones we adjust on the beach before sailing depending on who's crewing the boat.