We use 4 cylindrical 10x26 with really nice polar-tek material covers from Maine Point in SW Harbor Maine www.mainepoint
fendercovers.com. I've found this material much less abrasive than the canvas like cloth. We also use fender
boards that I made out of pvc pipe - each about 5.5 feet long - with drilled holes at each end through which I've run line
that ties off to the lifelines. The pvc is light, stows easily on deck and was some scrap sitting around waiting for a project. The arrangement works very well with pilings and ranges of tide.