Trailer guides can damage your boat if you run into them at high speeds. This is why it’s always a better idea to go slow and steady while loading your boat onto the trailer instead of charging in like a jock. This is especially true with pontoon tubes. If you run into the post hard enough, they can puncture the tube and let water in. As you can imagine, this is not good.  If you’re unsure of your abilities, then it may be best to start off using some simple PVC trailer guides as these have less risk associated with them.