The GCW and GVW are used by motorhome manufactures to stipulate weight as concerned with warranty of products. If they can show that an owner has significantly overloaded a vehicle, they may choose not to warranty to failed axle or transmission, etc. Each Manufacture states separately how much weight can be towed behind their motorhome. My argument to you all is to pick the lightest possible dingy and learn how to drive the combined weight safely. Check the owners manual of your motorhome for the towed weight limits, and the owners manual of the dingy for its curb weight and other towed limitations.
Lets drive safely and legally out there.
In another article, I will outline the merits of the available towed car braking systems.