Boating Tips


Posted 4/26/2011

Your Tow Vehicle Can Stop on a Dime – Can Your Boat Trailer Do The Same?

Your Tow Vehicle Can Stop on a Dime – Can Your Boat Trailer Do The Same?

Let’s face it; towing a boat down the road requires that you alter your normal driving habits to compensate for the mass on the trailer behind you. Swinging wide on turns, keeping the trailer in your lane, and hanging back a little farther from the cars ahead of you are all common towing practices.

However, when the minivan in front of us suddenly stops to check out that yard sale, we instinctively hit the brake pedal – instantly activating our tow vehicle’s brakes and the trailer brakes – allowing us to maintain control. Moments like these make us appreciate boat trailer brakes.

Do I Really Need Trailer Brakes?
The short answer is probably. The long answer is it depends on the laws of the state in which you live. States may mandate brakes on one axle, both axles, or establish weight criteria for the trailer to determine whether brakes are required.

Common sense factors into this equation. If you’re pulling a 14’ tin boat on a little single-axle trailer, you probably don’t need trailer brakes; however, if your boat is tipping the scales near the one-ton range or more, it’s in your best interest to have brakes on the boat trailer. You’ll need the additional stopping power to keep the boat behind your tow vehicle, where it belongs.
Check your state laws and use your noggin’ to trailer brake decisions.

Boat Trailer Brake System Fundamentals
The brakes on a boat trailer are hydraulic; that is, when the brakes are applied, fluid (under extremely high pressure) flows to the braking mechanism, activating the brakes to slow or stop the trailer.

Drum Brakes
Drum brakes use a small hydraulic cylinder (wheel cylinder) to push the brake shoes outward against the inside of the brake drum (bowl-shaped outer housing). Drum brakes work well, aren’t very expensive, and have been used in automotive applications for nearly a century. One might say that drum brakes are time-tested technology.

For all the plusses, drum brakes are difficult to clean (i.e. washing out debris and salt water, although add-on flush kits are available), don’t function when backing up, and need periodic manual adjustment to maintain optimum performance.

Disc Brakes
Unlike drum brakes, which are enclosed within the drum, disc brakes aren’t hidden from view, consisting of a thick metal disc (rotor) and a hydraulically operated caliper. The caliper is a clever clamping device that has a piston on one side of the “clamp” and an articulated mechanism on the other side of the “clamp”. Hydraulic pressure forces the caliper assembly to squeeze the brake pads on both sides of the rotor.

Disc brakes require less maintenance, are self-adjusting, easy to inspect and clean without disassembly, and deliver greater stopping power than drum brakes. And disc brakes work fine when you’re backing up the trailer – more on that in a moment.

Like drum brakes, disc brake systems have been around for decades, usually on high-end vehicles, but in recent years, the price of disc brakes has come down. Now disc brakes are on all types of boat trailers.

Because disc brakes operate in forward and reverse, backing a disc brake trailer up an incline (such as a driveway) can be an exercise in frustration - if you don’t have a reverse lock out solenoid.

Here’s how it works: when you put the tow vehicle’s shifter in reverse, the backup lights send power to a small solenoid on the boat trailer. When energized, the solenoid closes a valve in the trailer brake system, preventing brake fluid from flowing to the brakes.

Once you move the shifter from reverse, the backup lights go off, the trailer brake solenoid is deactivated and the trailer brakes return to their dependable, forward function mode. 

You can also manually disable the trailer brakes with a lockout pin, if you plan to be moving the trailer around the yard frequently. Just make sure to remove the lockout pin before towing.

Actuator/Hydraulic Surge Coupler
The “hitch” part of a boat trailer equipped with brakes is called an actuator or generically, a hydraulic surge coupler.

An actuator functions by the kinetic energy of the trailer moving towards the tow vehicle. When you press down on the brake pedal, the trailer pushes against the tow vehicle, causing the actuator to telescope together and apply force to its internal master cylinder, pressurizing the hydraulic fluid in the brake lines, thus activating the trailer brakes. 

Due to the differences in the operating mechanisms of drum and disc brakes, you must use an actuator specifically designed for the trailer brake system you’re using (drum or disc).

Stopping Point
We’ve covered the highlights of typical boat trailer brake systems, but obviously, there is a lot more material to cover. 

Read your boat trailer owner’s manual for information specific to your trailer. Or, jump on the web and check out the various boat trailer manufacturers’ sites to further your brake knowledge inventory. Y

Image Credits
Ranger® Boats
Tie Down Engineering, Inc. ®