Tp-5 boat trailers with too little tongue weight tend to do what?

Boat trailers with too little tongue weight can lead to out of control swaying and fish-tailing at highway speeds, may leave the road, hit other vehicles on the road, or overturn.

Tongue weight is the amount of weight that is placed on the tongue of the draw-bar. It it mostly recommended to weigh first the trailed boats for precautionary measures.