Look at the picture in the bent bow update post. That's a 5 inch contour port. Slight gap at the center from a little too much contour but probably fits better than the flat one. Turns fine. I just went out and laid a straightedge across the deck behind the rear beam and it's got more radius than in front of the front beam where I put my port. I would go for the contoured port. From Rick's store:
http://store.catsailor.com/tek9.asp?pg=products&specific=jmorjrjsf0Tom
