Boat trailers come in several sizes to accommodate a variety of lengths and weights of boats. For each increase in size and weight, there is a range of boats that fit a trailer. The better your boat fits its trailer, the easier and safer it will be to tow. A boat trailer that fits improperly is a serious hazard that creates a danger to you, your family and everyone else on the road.
How to Set Up a Boat Trailer for a Boat
Make sure any trailer you purchase for your boat is appropriate for the weight of your boat. There is a plate located by the winch stand with the maximum weight for the trailer stamped in it. Measure from the end of the bunks, or rollers, the back of the boat is resting on to the end of the boat. Make sure there is less than 31" so there is sufficient support for the transom, or the back wall of the boat.
Drive to a nearby trucking company, granary, junkyard or scrap metal yard that has a drive-on scale. Weigh the combined weight of your truck and loaded trailer combined. That is your GVWR (gross vehicle weight rating). Your tow vehicle's maximum capacity must include the weight of the vehicle itself, passengers, gear, and the boat and trailer.
Calculate the tongue weight of your loaded trailer. A tongue weight that is too heavy will create drag, be hard on your transmission and use more fuel. A tongue weight that is too light will cause the vehicle to sway while transporting. Proper tongue weight is 5% to 7% of the total weight of the trailer, boat and gear. Rest the trailer coupler of a boat less than 2,500 pounds on a household scale.
For boats larger than 2500 pounds obtain a brick the same height as the household scale. Place the brick and the scale 3 feet apart. Lay a pipe down the center of the scale from just under the readout, to the bottom. Lay a second pipe from top to bottom on the brick. This will center the pressure of the load. Lay a 2-by-4 piece of wood across the pipes. Re-calibrate the household scale to zero to compensate for the extra weight of the pipe and wood frame. Place the trailer coupler on the crosspiece. Multiply the readout on the household scale by 3.
To obtain readings on boats that still read heavier than the scale allows spread the brick and scale further apart in one-foot increments. Multiply the readout by the number of feet of separation between scale and brick.
Move the rearmost support bunks back to reach the end of the boat. Increase or decrease tongue weight by moving the boat support bunks. Move them back to lighten the weight on the tongue; move them forward to increase weight on the tongue.
Move the winch stand further back to lighten the weight on the tongue once the bunks are as far back as possible.
Secure your boat to the trailer at all times with the appropriate tie downs for maximum towing safety. Secure a transom tie-down from each hook on the transom to the corresponding hook on the end of the trailer. Transom tie downs prevent your boat from lifting off the trailer and landing on your tow vehicle during emergency stops. Secure the bow of the boat with a safety chain connected to the winch hook on the bow and the corresponding hook below the winch stand. The bow safety chain protects your boat from falling from the trailer when a winch strap fails. The bow safety chain acts as a further tie down strap to prevent lift off as well.