Darn Trailer Brakes is locking up !

[nymack66]

I am always diligent about cleaning and washing my Boat and trailer after a salt-water run,
However I trailer the Boat to the lake today and the port front axle is locking up I can clearly see the dust from the pads and the rim and hub was very very hot the trailer is (all wheel disc brakes system)
Question is what can I do to prevent this? I am disappointed to see a brand new trailer locking up like this after on season.
Any idea on what I could have done differently to prevent this?
This is the culprit notice the wear on the rotor ?


The rest looks like this