Ok, I went with Nota's suggestion, thanks Nota, and set up a strap and wood system. At first nothing moved. The hog at its worst point was still 17mm. I then drilled out most of the rivets holding the aluminum gunwhales on and the hog immediately went to around 5-7mm.
My plan is to spray the inside bottom of the boat with black plasti-dip and set it out in the sun for a spell. I'm hoping the heat will soften it a little bit. Once it is where I want it, or slightly past, I will drill new holes for the gunwhales and re-rivet it. I will then peel off the plasti-dip and let the hull cool.
Here is a pic of the contraption; the orange strap is connected to the ends of the boat and goes over a 2x6 T shaped piece of wood.
Thanks guys.
