If you have repaired the keel before and you have a penchant for messing it up on rocks or ice (as do), consider adding a brass rub strip on both ends. I tried the fibreglass thing initially: it wore off after the first year. I replaced it with an ash rub strip and that splintered after three. I added brass to the bow keel 5 years ago wtih tremendous success. This year I added brass to the stern end. The brass is virtually indestructable...at least I haven't found a way to wreck it yet and I have tried hard. ;)

Robert N Pruden