It is precisely because of "Acts of God" that sailors are required to tie down their boats. Right? So that is not a valid excuse.

If they signed a contract that required them to tie down their boats, then I would presume they are legally bound by it. Did the contract further specify that they would be responsible to pay for any damages inflicted by their boats if not tied down properly?

Regardless, if they were in breach of the contract, it seems obvious that the park (if that is who the contract was with) would not allow them to keep a boat there any more.

And, as Jake said, one would think that the damages would be covered by the homeowners policies of the owners of the boats that caused the damages.

Sometimes the only recourse is to go to small claims court. I realize it is a difficult situation, not wanting to make enemies within the club -- but that is going to be the case anyway, so why not let it be decided by the law? That's what we do when we have conflicts in sailboat racing, and we accept the verdicts, and we all manage to still be friends.