I only know of one strike firsthand.

This was just a few weeks ago. We had finished a cabin boat regatta and pulled into dock. We were at awards when a good storm rolled in. We saw a 41 foot boat that was docked take a direct hit lighting up the top of the mast. This was the tallest mast in the harbor. Nobody was on board at the time. The hit blew out all the instruments and blew tiny pin holes through the fibreglass near the keel. When we went down to check it nothing was visibly wrong with the boat. The boat didn't take on any water from the fibreglass damage. I saw the strike and while it was loud it didn't seem like a very large bolt. The boats engine started right up and other than the instruments the boat seemed fine at first until they pulled the boat to look underneath.

I would still like to hear from someone that has first-hand knowledge of a boat being hit while sailing. Though I don't know why this boats incident would have been any different if it had been sailing. But perhaps there is something that disipates the charge when sailing.