Not to condone what you are thinking but as someone else mentioned what is going to be your actual weight. Don't load water tanks put what would be your normal amount of clothes, and whatever toys you were going to haul and weigh it. you could be far away from the 18,000 that the trailer could handle, it which case you have a margin of safety with trailer brakes/tires/suspension that you are not using say if the rig only weighed 13-14,000 pounds loaded the way you would haul. ie designed to haul a race car spare wheels and tools but you are only loading a quad.