Boat Trailer locking up

[crash68]

Update, went to the boat dealer yesterday, they never gave me the lockout pin for the trailer. Put that in last night after throwing the boat in the water, zero issues!

maybe it's just how you typed it, but put the lock out pin in before you back down the ramp when launching. Pull the pin once the boat is loaded and your heading home. That pin keeps the brakes from engaging when backing up

 

[TomB 1269]

Willing to bet its the brakes. When it bounces off the road it places forward pressure on the tongue. The brake activates stops the wheels from turning as they are in the air and as the tire makes contact with the road again it will skid slightly before it turns over.

Surge brakes used to be common on old campers like popups etc. and they sucked when pulling over bumpy roads as the coupling would be moving in and out with each bounce causing a jerking effect with the brakes.