The fiberglass can compress of course. If you search for photos of keels being repaired, you will find photos of lead keels with the bolts being _rebedded_.
MARSKEEL website is especially cool. Some of their staff worked for C&C. They not only make new and repair old lead keels (both oem and custom) , they also make custom bulbs to reduce draft. I had some hope of doing that last year but unfortunately not an option for the stupid shark fin keel design.
