So I guess I should have picked it up before but I am clear now that many of you feel that towing doubles is unsafe at any speed/gcvw/length. I apologize for unnecessarily stirring this topic up again.
I've seen enough folks going up and down the road towing doubles and I think that with a short, light 5er and surge brakes on the boat trailer (mechanically actuated hydrolic trailer brakes when the trailer pushes forward on the ball hitch it activates the master cylinder) that you could probably tow a double safely. But there are a lot of ifs, if the 5er trails good, if the boat trailer trails good, if the frame on the 5er is heavy enough, GCVW, length, no hope of backing it up more then a few feet, whipping it, dropping your boat somewhere at a campground parking your 5er then going back to get the boat, Spouse thinking your nuts for even entertaining the thought, etc...
Thats a lot of ifs....I think too many for me.
Taking this all into account, I'm now thinking for my families needs probably a Truck Camper and towing a boat directly behind the truck is a better idea for me. I understand that theres still ifs going that route as well but it seems for my needs there's a lot less.
Take care and thanks for the comments.
Since you guys discuss weights and overloaded trucks an awful lot I figured I drop a link I found about a fella discussing his TC setup. I know this isn't the TC area but seems like he's gone to a lot to "toughen up" a way overloaded rig.
http://www.truckcampermagazine.com/index.php?option=com_content&task=view&id=791&Itemid=34