What happened Dave? Masts out. No precariously tall fin keels. Looks like good stands/cradles beneath the boats.
Your boat appears to have been on jack stands? 2 - 3 per side? Chains?
Was it wind or some other factor that caused the boats to tumble?
@TomY The proximal cause was a storm with ~ 40 mph winds. I don't think there was any one fatal flaw, it was a combination of several factors:
The boat faced NW and in close proximity to the barn. If you stood on the foredeck, there was no land between the boat and Toronto some 130 miles away. The wind no doubt hit the barn and buffeted the boat with apparent winds in excess of 50 mph.
The asphalt surface was solid, but not perfectly level. Water and ice may have gotten under the jack stands.
The cover added windage.
The number of jack stands was marginal. It was (and still is) a 30' boat that had 2 jack stands per side and one under the bow. The rule of thumb is one jack stand for every 8' of boat. We were on the edge.
The jack stands were not made by Brownell.
While I have no evidence, I believe the keel was not properly blocked. I believe it was only blocked in the middle in one place. Standard practice is to block the keel in 2 places fore and aft. This prevents the boat from rocking fore and aft on the blocking.
This was only the second year the marina was using jack stands, so they were inexperienced with them.
If I put all this together I think when the storm blew through the boat started rocking back and forth on the inadequate keel blocking which was made worse by the cover (more windage) and the proximity to the barn which caused more buffeting. Eventually one of the jack stands moved (probably due to the ice underneath) and failed. Then everything went to hell.
The marina and BoatUS insurance made it all right and except for an overworked (or procrastinating surveyor) The whole process was relatively painless and I only lost a couple of weeks of sailing.