A Guide For Understanding Trim Tabs
Maybe they came with the boat, or you decided to add them aftermarket, but knowing how to properly utilize trim tabs will can change how you boat. In this article we’ll discuss what trim tabs are, what they do, and how to use them effectively.
What Are Trim Tabs?
Trim tabs consist of two adjustable metal plates that can go up or down independent of each other or move in the same direction simultaneously. They are attached to the stern of the boat at the waterline and improve the handling characteristics of your boat by adjusting its attitude (pitch axis) and roll in the water.
Types of Trim Tabs
Trim tabs come in a variety of styles. There are self-leveling, bolt/electric, bolt edge mount, classic style hydraulic, and high-performance variants. If your boat does not come equipped with tabs, your local yard may be able to set you up with the right type and size for you boat. Generally speaking, selecting the widest tabs which can fit and mount on your transom will be the most effective.
What Do Trim Tabs Do?
Get on Plane Faster
When used at a slow speed, simultaneously deflecting both trim tabs down will allow your boat to plane faster and reduce how much your stern is squatting in the water.
Reduce Bow Rise
Another result of deflecting both trim tabs down and bringing your stern “out of the pocket” is that your bow will also go down giving you improved visibility.
Correct For Listing
If the weight of your cargo or passengers is causing your boat to be “out of trim” and listing to either port or starboard, properly applying trim down on the high side of the boat will correct the roll and balance the boat.
You can check your boat’s trim by looking at the horizon and seeing how it relates to your bow cross-section. If one side is high, your boat is out of trim. To correct, simply depress the trim tab on the same side that is riding high. Use a half second burst and wait a few seconds to observe the effects. Repeat until you achieve the desired results.
Correct For Porpoising
You may have been here – getting up to speed and on plane, then and a few moments later your boat starts to porpoise. It usually starts light then ends with you jumping wakes that don’t exist. Many inexperienced boaters pull back on the throttle and even lose their plane. With trim tabs, you can simply keep your speed and deflect both trim tabs downward (bow down) about one second at a time until the boat stiffens up. You can also use your trim tabs in combination with your power (outboard motor) trim.
Trim tabs can help a lot in rough water environments. With practice, you’ll soon be using your trim tabs to mitigate a head sea, a following sea and a beam sea. When heading into a head sea, trimming down will allow your vessel to “grip” the waves and keep the boat from bottoming out.
Other Things To Remember
Yes, boaters do it all the time. There is too much of a good thing. If you pass the boat’s perfect state of pitch for the speed you are at, you can drive too much force on the bow causing more drag. This is called over-trimming.
Keep Your Inputs Small (At First)
Your speed, RPM and the spray off the sides and rear of the boat all give clues to indicate when you are properly trimmed. Usually, speed will increase, then start to diminish. Set your trim tabs for the top of this arc. Upon first learning, keep input bursts to a half second. Later, you may recall that proper trim for X speed is equal to X number of seconds on the buttons. Once you are there, do a micro adjustment or two for top speed.
By properly using trims and in combination with your boat’s power trim, you can correct for several trim issues and improve the handling of your vessel. If you don’t have them already installed, you may wish to do so. If you do have them on board, be sure to use them properly.