You must know of the term GCM......
just because it's plated 3500kg towing doesn't mean you can tow 3500kg with a boat,outboard,fridge,350kg on the ball ,extra fuel etc etc etc..on the tow vehicle.
to tow 3500kg some Can Carry VERY little weight on the tug..
some of these tow vehicles with 3500kg towing are way over their safe towing limit...
do a bit of a search on real tow weighs / capacity
cheers Danny