Why Is Tongue Weight Important When Towing Your Boat?

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Many boat owners need to realize how crucial knowing the tongue weight is for proper towing. Why is tongue weight important when towing your boat?

Knowing the proper tongue weight of the trailer is the key to effective towing. If you do not have adequate weight on the tongue, the trailer may sway from side to side, losing control. If there is not enough weight, the trailer could overwhelm the back end of the towing vehicle.

Let’s face it. The last thing you want to happen on the way to the reservoir is to cause an accident with a swaying trailer. This vital information can keep you and everyone on the road safe, whether pulling a boat, a flatbed trailer, or even a camper. Unfortunately, many trailer owners do not give proper tongue weight any thought, which is a shame. The NTHSA reports that nearly 55,000 accidents occur each year that involve the towing of a trailer. (Many of these accidents are deadly or, at the very least, cause extensive damage to vehicles).

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What is Tongue Weight?

Every time a trailer gets hooked up to a hitch, the trailer tongue exerts a force on the ball. There is a downward force of gravity on the trailer, and the connection to the hitch causes an upward force. Then a pulling force exerts itself on the tow vehicle and trailer.

The tongue weight is the static force applied as the front of the trailer pushes down onto the hitch's ball.

How Does Tongue Weight Affect my Vehicle?

As we mentioned, if a tongue weight is too light, the trailer and your boat will move side to side, and the trailer could disconnect from the ball and jackknife. A trailer with too little weight doesn’t exert enough downward force on the trailer ball.

(When I was a service advisor for a car company, many times people came in with damage to their trailers and SUVs due to a trailer they were towing getting away from them. My advice is not to think it won’t happen to you because it can).

If the tongue weight is too much, the towing vehicle will be hard to steer and less responsive when navigating a corner. This is also dangerous because the trailer is pushing the rear of the tow vehicle, and the increased weight is lifting the rear of the tow vehicle. The trailer will push the car in the direction it has been traveling, which might be different from where you want your trailer to go.

How Can I Calculate my Tongue Weight?

Calculating tongue weight doesn’t take a degree in physics (although that could help, I suppose). Most car and truck companies will list their vehicle's total gross towing weight. By weighing the trailer and tow vehicle together, you will have a total gross weight of what you are attempting to tow.

But you still don’t know the tongue's weight. To calculate that figure, you must weigh the trailer without being hitched to the towing vehicle. Subtract the weight of the trailer from the combined gross weight (towing vehicle and trailer), and that number is the tongue weight. A proper tongue weight for a standard trailer hitch is about 10 - 15% of the total loaded trailer weight.

If the weight is within the correct parameters, you are about to tow a properly balanced trailer.

What if My Tongue Weight is too Light?

If the figure is too light, don’t fret. Move more load to the front of the trailer (boat). Most towing companies advise that about 60% of the load should be over or ahead of the trailer’s tires. Load the trailer evenly from side to side.

What if My tongue Weight is too Heavy?

If the tongue weight is too heavy or more than 15%, your vehicle may become less responsive, especially when executing a turn or braking. If this is the case, you may have to leave some of the gear behind. (You will need to find a way to lighten the weight of the trailer and boat).

Is There a Way to Check the Weight of my Loaded Trailer?

Many truck scales will allow you to weigh your trailer and truck for a small fee. Call ahead and see if they have a charge and when you might be a good time to bring your truck and trailer by. Be sure to load it as you would if you were headed to the reservoir or whatever destination you were planning.

Can I Use a Bathroom Scale to Calculate Tongue Weight?

If you think the tongue weight is less than 300 lbs, then you can use a bathroom scale to find the tongue weight. Simply place the jack or stand from the tongue onto the scale and see what it says. (You should place a piece of plywood onto the scale to keep it from damaging the scale. In addition, most bathroom scales top out at 300 lbs, so if the scale reads 300, you should have a place with a truck scale to confirm that figure.

Are there other Things I can Do to Keep My Trailer from Swaying?

Most modern pickups are equipped with a trailer sway assist program that uses a sensor inside the steering wheel assembly to monitor the vehicle's movement. The computer helps slow the vehicle and trailer down when the sensor detects a problem by gently applying the brakes.

In addition to trailer sway assist, electronic brake controllers are essential when towing. The trailer braking system has an electric connection, and the truck can apply the appropriate slowing force when needed.

Safety chains should always be used when towing. Make sure the chains are large enough for use on the trailer you are towing. The safety chain from the truck to the trailer can keep the trailer connected long enough for the driver to pull over should an event happen. If there is no chain, the trailer could sway into oncoming traffic or cross lanes, creating a huge problem.

What is the Difference between Different Class of Trailer Hitches?

There are several levels of trailer hitches, so it is vital to know the differences.

Class 1 Trailer Hitch

This trailer hitch class is most commonly used for small light-duty trainers, small john boats, or bike racks. Class 1 has a maximum towing capacity of 2000 lbs. If you see a hitch on the back of an SUV for Gramp’s scooter, this is likely a Class 1 hitch.

Class 2 Trailer Hitch

A Class 2 trailer hitch has a towing capacity of around 3,500 lbs. Again, you will find these on all kinds of cars and small SUVs. They are designed for hauling small trailers, boats, or cargo containers.

Class 3 Trailer Hitch

A Class 3 hitch has a towing capacity of up to 8,000 lbs. This unit is often the hitch you will find on the back of a pickup and help tow boats, small campers, and the like.

Class 4 Trailer Hitch

This hitch is installed on full-sized pickups or trucks and is used to haul larger trailers or boats. They have a maximum towing capacity of up to 10,000 lbs. Many pickup owners like having Class 4 hitches on the back of their trucks.

Class 5 Trailer Hitch

This big daddy of trailer hitches has a max towing capacity of 18,000 to 20,000 lbs. They are designed to haul horse trailers, large recreational vehicles, and commercial trailers.