The problem is that I have a tri hull and the top of the pipe/roller do not go up to the sheer when the trailer is in the water, and unless the boat is perfectly centered the post ends up missing the outside of the hull and grinds against the "V" inbetween, not to mention the guides really weren't helping me get the boat on the trailer.
My original fix was to just put heavy PVC pipe over the metal post, long enough that it would be above the sheer when loading the boat on the trailer. That worked fine, the PVC stood up to good hits while trying to get the bow between the posts. And while I had solved the problem of scraping the hull, the guides still weren't helping me get the boat on the trailer.
To make this really work, I needed to get the posts farther apart, so I had a welder cut the posts off and put (square) sockets on the trailer. This would let me have an outward tilt to the poles and also I could adjust the posts outward in the sockets allowing more room to get the boat in. And it worked really well...except the posts had to be removed when I trailered the boat because they stuck out making the load over 9 feet wide. I was about to make "T" handles to attach the new posts in the sockets so I could easily remove the posts, but that would mean I'd still have to find a place to put them.
Finally, the ultimate solution became apparent. I'd make a strap that connected the two posts at the top. It would be short enough that it would pull the PVC against the hull, thus narrowing the width and eliminating the need to stow the posts.