When Mike Goodwin and I removed and filled the through hulls on Commander #105 the hull was more than 1" thick closer to 1 1/2 " and the glass seemed like new. I have run aground hard at full speed and there was no damage to keel, the 6 hp Nissan 4 stroke was able to back out with some little difficulty. Note that my good ol' boat survived having another bigger boat on top of it and crushing waves and all kind of hits from wrecked piers and other boats during hurricain a couple of years ago that sank or severly damaged most newer boats in and around same marinia. This is one very tough old boat, very much heavier then new ones of same length today with such sweet lines too. I will be posting photos soon as I get the mast back on and deck painted.