Thanks for the credit but those were not my photos, but it did copy his design somewhat. I have found that if you cut the pipe a little long and force it on it creates a bow but sometimes it might slip off, what i did was hold it in place and heat up the center of the bow and it formed a nice permanent arch, i did not use the 45's. while it was raining yesterday i noticed that water was still ponding between the bows so i attached a few bungee cords down the center attached to each bow, you might have to also use a bungee to attach to the front and rear of the boat to counter act the other bungees and keep the bows from falling in toward one another. This worked perfectly and totally fixed the ponding issue. I used 1.5" by .75" tees, with .75" bows