What Is the Main Function of a Boat Trailer’s Safety Chains? PLUS Other Safe Towing Tips

Published Categorized as Boats, Boat Gear and Accessories

While most of my blog focuses on boats you can live aboard, trailerable boats allow many people to get out on the water before they get that big boat. They’re great fun and can take you to your local lake or the Florida Keys for a week’s vacation.

Here’s a look at some critical items every boat trailer should have. I’m including the answer to “what is the main function of a boat trailer’s safety chains” and some great tips to keep you safe on the highway.

boat trailer safety chains

Table of Contents

The Main Function of a Boat Trailer’s Safety Chains

The main function of a boat trailer’s safety chains is to serve as a fail-safe mechanism in the event of a hitch system failure. These chains are welded to the trailer tongue and connected to the tow vehicle’s trailer hitch, ensuring that if any part of the hitch system fails, the trailer will not detach and roll away independently on the highway.

The practice of crossing the two safety chains under the hitch provides added security by creating a cradle for the hitch, preventing it from hitting the road if it becomes detached. This system acts as a critical safety measure to prevent accidents and ensure the trailer remains attached to the tow vehicle, even as a last resort.

What is a Boat Trailer?

A boat trailer is a specialized type of trailer designed to transport boats over land. It consists of a frame equipped with wheels, onto which a boat can be securely loaded, transported, and then unloaded at a destination, such as a body of water or storage facility

Why Tow Your Boat?

Towing small boats means you can go anywhere and keep them at home — saving you from paying expensive marina and boatyard fees.

Depending on where and how you boat, towing might be something you rarely do or something you do every time you hit the water.

But boat trailers are special kinds of beasts. They have their maintenance requirements—when was the last time you lubed your bearings, anyway?—and they have many steps to get rolling down the highway safely. 

boat trailer

Trailer Safety Chains and Other Features of Boat Trailers

Boat trailers have a few key pieces of safety equipment that you should be familiar with. 

The boat trailer’s safety chains are welded in place on the trailer tongue. They are connected to your tow vehicle trailer hitch as a last resort to ensure that if any link in the system fails, the trailer won’t roll off on its own down the highway.

There are two safety chains. Connect the safety chains underneath the hitch, crossed over one another. That ensures the hitch will fall on the chains, not the road below. 

If your trailer has brakes, it may have a third safety chain that engages the brakes should the trailer come off the hitch.

The ultimate goal of any tow vehicle driver should be never to need their safety chains, though. Two locks on the trailer hitch should keep it attached at all times. 

One keeps the hitch ball locked into the receiver. It is usually secured with a cotter pin, but you can purchase lockable trailer pins to deter theft. 

The second locking pin is on the trailer tongue, where the coupler fits over the hitch ball. There’s a lock that you press down to keep it on the ball and a pin that keeps that lock held in place. Again, you can purchase lockable pins that deter trailer theft. 

A good transom strap is the final towing equipment you should have for every tow. This keeps the boat connected to the trailer, even as it’s bouncing down the highway at speed. Some boats use one large strap that spans the boat’s beam, and some use two smaller ratchet straps attached to the eyes on the boat transom.

Tips and Tricks to Safely Tow a Boat

Boat Safety Chain Basics

Cross the trailer chains and attach them to the eyes of your trailer hitch. Should any part of the hitch fail, the chains should catch the trailer tongue before it hits the road. It won’t tow well—they are a last resort to help prevent a catastrophic boating accident

Your safety chains should not touch the road as you drive. If you hear the jingle-jangle of chains as you drive, it’s not Rudolph and Santa’s reindeer. It means your chains are too long, and you might need to adjust how you attach them. Just make sure there’s still enough slack for the trailer to turn freely.

Brake Safety

In most states, if the trailer weighs more than 3,000 pounds, it must have a brake system. Most boat trailers have surge brakes. 

Surge brake systems have an extra safety chain that engages the brake if the hitch system fails. Make sure it’s attached along with your other safety chains!

Transom Straps Are Critical!

Sometimes, there’s a misconception that gravity alone will hold down a boat. Truthfully, the regular bumps a trailer goes over on the highway can make it lift off the trailer. Once that happens, it only takes a little swaying or turning movement to make a catastrophic event when the trailer returns to Earth.

To prevent this, the trailer and boat must move as one. They must be connected so that the front and back of the trailer and boat cannot come apart. The front is connected at the bow eye with the winch strap, but a robust transom strap must connect the back. 

Mind Your Gross Vehicle Weight Rating

Please pay close attention to the GVWR of your towing vehicle and the trailer itself. It can often be difficult to pin down your precise towing weight, so be conservative. Don’t forget to add fuel in the boat’s tank (6 pounds per gallon) and water if it carries onboard water (8 pounds per gallon). Owner gear can add up to at least a few hundred pounds on most vessels. 

Outboard Positioning—Up or Down?

There are two things to consider when towing an outboard boat. You can tow it with the engine tilted up or tow it with it in the fully down position. The right answer for you will depend on how much clearance the prop skeg has with the road. You don’t want your lower unit scraping along the pavement at every bump.

But many engine manufacturers will tell you that their motors aren’t designed to be towed with the engine tilted up. This puts a lot of force on the hydraulic tilt unit as the heavy motor bounces up and down. It’s not designed to take that. 

If you can’t tow with the motor down, and you can’t tow with it tilted up either, what’s a boater to do? Thankfully, several brackets on the market support the motor in the tilted position for towing. This takes the stress off the hydraulics and keeps your lower unit safely off the pavement.

Here’s a great video from Boats.com that covers the basics of safely towing a rig on the highway.

Tow Safely Each Time By Knowing What Is the Main Function of a Boat Trailer’s Safety Chains

Towing a boat is fun and allows you to access watery adventures anywhere you can drive. But towing takes practice, and there are a lot of new skills to master. Using a hooking-up checklist is a good idea until you have the basics of a safe towing setup down pat. 

For more boat safety:

Trailer Safety Chain FAQs

Why do you cross the safety chains on a trailer?

When the chains are crossed, the hitch will be caught should any one component fail. If the chains are not crossed, the hitch would fall to the road, and complete loss of control of the tow vehicle is possible.

By Matt C

Matt has been boating around Florida for over 25 years in everything from small powerboats to large cruising catamarans. He currently lives aboard a 38-foot Cabo Rico sailboat with his wife Lucy and adventure dog Chelsea. Together, they cruise between winters in The Bahamas and summers in the Chesapeake Bay.

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