In my old 14ft tin boat I used a pedistal that I bolted to the seat with a big chunck of 1/4" stainless backing plate. I got the pedistal at outdoor emporium (don't know if they still have them) but they were basically a 2 1/2" or so pipe with a plate welded on each end that had holes drilled in them for mounting to the boat and holes for mounting the base of the downrigger on the other end. Pulled around 12lbs balls for alot of years with no problems.