[bulletbob]

Re considered my first reply when I re read your post and saw that your boat is aluminum..
Personally myself, I would use PT, making sure it was good and dry, and then paint or stain it, and use slick sliders with stainless screws, BUT my aluminum boat is older..

However, in your case, if you have a newer boat and worry about it getting scratched using sliders, and are using carpet, PT would not be the way to go.. The PT wood itself would need to be constantly touching the aluminum boat surface to cause issues really, but to be absolutely sure just use untreated wood..