With the great help of two "Buzzers" (JBL & Chip - Thank you very much), I've constructed an awesome platform on the gunwale of my 13' NRS otter raft. It was made for the dogs, as you can see. I also made center and front floors, and they love that too. The older dog was afraid of whitewater, but yesterday we did 16 miles including 3 stretches of Class III and by the end of the trip she went through the whitewater with her feet up on the front of the boat! She became a boating dog yesterday, and so did the puppy.
The material is polymax overlapping poultry floor, found at this link:
PolyMax Poultry Overlapping/Kennel Flooring
I used cardboard to make a template, cut it with a jigsaw, and filed it smooth with a panzer file. That is a sort of a file, but I mostly use it for taking off large globs or peelings of ptex on skis. Available at local hardware and actually called a Surfoam Versaplane. Then lots of straps to hold it down, and actually one piece of wood for support next to the cooler.
Hold on, the photo upload isn't working
If anyone wants more information, just PM me and I'll gladly pass it on.