I know the feeling. I broke a daggerboard (well about 7cm of the trailing edge was non-existent to about 1/2 way up) on some rocks that are supposed to be a meter under the water , and are not signposted in any way. that was on my paper tiger. it's a bit of a jolt when you are sailing along quietly and all of a sudden your boat wants to pick it's nose up and you hear a sickening crunch from underneath.