Let’s do some simple math. Imagine your winch is mounted 24 inches above the trailer tongue. When you tension the winch strap with 1,000 lbs of force (common when retrieving a boat against current or wind), the moment (torque) applied to the weld is:
A "trailer win crack" most commonly appears at the or directly in the heat-affected zone (HAZ) of the steel tubing, just above the weld. Why? Because when you crank that handle to pull a 5,000-pound boat onto the bunks, the winch stand acts like a lever. The top of the weld experiences tensile stress (pulling apart), while the bottom experiences compressive stress (pushing together). Over time, steel becomes tired. Trailer Win Crack