I changed the windows in Chinook (hull 447) last winter. It was relatively easy to remove the old windows with a putty knife to cut the old sealant. I used the old windows as templates for the cutting new ones. The most difficult part was scraping all the old bedding compound off the boat to prep for the new windows. I then bedded the new windows with 5200. One thing to be aware of, is the sides of the house have a little curve to them. If you try to just put a flat window in, either the front or back will not seal. I used a few 2x4's to leverage some weight against the new windows to press them into the curve of the boat.
