Low pressure in a tire gives a different wear pattern than what the picture shows. Inside wear usually is from a bent axle, or a weak spring system. The boat is to heavy for the trailer springs if the axle isn't bent. The trailer should have a camber to the axle when the boat is off of it. The axle should have a rating sticker or stamp on it also. Even with a relatively light 3500lb axle, I doubt your boat weighs that much.

Oh yea, those tires are dangerous. They are Shot.