Trying to figure out the total weight of a boat and trailer that I'm looking at buying. I know that the gross weight of the boat is 3,900 lbs but I', not sure about the weight of the trailer. It is a double axle trailer with surge brakes. My guess is that it the trailer must weight approx 500 lbs. Does this sound about right for the weight of the trailer? Your assistance on the trailer weight would be appreciated.