it also reminds me of this:
http://www.autoblog.com/2006/07/27/c...mazdas-aboard/
anyways, it happens.. and more often than people think...
just cuz it is lashed and secured doesn't mean it can take anything that is shot at it..
the vessel probably experienced a lot of roll and the lashing wasnt done right, cars got unlashed, slid, and hit other cars....
that's what I'd assume happened..