Well, since I have never had nor seen a small white cap on any of my cruises, I can't comment on 'bumpy'. Ours were so smooth it was almost ridiculous. Besides, I can't imagine the very tail of the ship being bumpy since they are just over the props which should be the smoothest of anywhere on the ship. But, to each his own. Actually, I was hoping no one would like them so they would be easier to get.