I also own a P26 and the "crack" in the keel/hull joint is very normal for this boat. I have it every year at haulout. Quite surprised you've never seen it before. What you need to do is torque your keel bolts every season and just fair over the crack. Just did the same to my boat yesterday. Check out Dan Pfeiffer's description of the keel/hull joint. If you haven't been on his site, it has a wealth of info on the P26.
Top of the keel