Good point to bring up. It is important to not forget that the trailer's tongue weight should always be between 10% - 15% of the trailer's total weight. This figure will be somewhat different for each individual trailer, and can be greatly affected by such things as distance from the wheels to hitch length, length aft of wheels, and by the trailer loading configuration (both what's installed and what's carried).
Fishtailing is generally caused by too light
of a tongue weight, so please take into account any weight shift changes that will be created by adding such additional loads, particularly at the rear of the trailer. Any changes will be less pronounced by moving the load closer to the wheel area, and likewise the further from the wheel area you move any given weight, the more effect it will have on overall weight distribution. Sometimes loads can be counterweighted by moving heavy items (like batteries for example) to different locations. Putting the battery
, or other heavier items, on the tongue will help to counter the added leverage of the additional load on the rear of the trailer. This hasn't been much of a problem for me personally because, as those of us who have them know, Casita
trailer tongue weights generally run a little on the heavy side as it is, but light
weight trailers will notice more pronounced handling difficulties by not properly maintaining the 10% - 15% weight requirement on their hitches. Hope this helps.