Jack, I have just remembered (prompted by your post) a New Zealand device that I read about some years ago. Imagin if you will a stainless steel tube about a foot long which is welded to a free movement stainless ball and socket arrangement, this in turn is welded to a flat fixing plate which is fastened to the gunnel.
In use, once a fish is struck the butt end of the rod is dropped into the tube and held one handed above the reel whilst the other hand turns the reel. As the pivoting fulcrum is now fixed to the boat all the effort used is from the arms and shoulders.
I am certain that one could be fabricated quite easily.
Mad Mike