This is a wake-up call for me as I drag my boat with a truck camper on 95% of the time so I have to use an extender which lowers my rating and limited me to a lighter boat than I'd like to have purchased. I am curious about the adjustable hitches though ~ seems [like Cap'n Ron mentioned] tihe weak point would be in the side flanges where the ball pins mount through.
I remember back around a dozen years ago or so, I saw a boat and trailer sitting well out into the alders at the bottom of Turnagain Pass [over the guardrail] on the curve before just before Ingram Creek. Yikes!! So glad we are not reading a different outcome from this event.