The boats on trailers with masts DOWN were fine. They all had sail boxes and were pretty heavy. A Capricorn with MAST UP, on a heavy trailer was fine.
A H-16, with mast up, on the trailer was fine.
My boat, mast UP was tied to the trailer and flipped anyway, trailer and all. My rigging hung-up on the trailer of the Capricorn parked next to me. My boat suffered no damage, neither did the Cap. My trailer does not have a sailbox. I have intentionally tried to keep my trailering weight down.
I will add a sail box to my trailer, with very little consideration of weight and keep some tie down anchors in it. My preference will be to keep the boat on the trailer with mast down.
Thanks Jennifer, Fred, Bryan, Chuck, Mavis, David, Kathy, Paul and Terry. I hope I haven't forgotten anyone. It took all those folks plus Matt, Tim and me a couple of hours to police up all the bits and untangle all the spahetti.