Bennett Control Switches & Indicators

About Bennett Switches

Trim Tab Indicators and Automatic Controls

Article courtesy of Bennett Marine

As a boat owner, you have loads of choices when it comes to electronic upgrades. Yet did you know these devices also apply to adjustable trim tabs? Yes, those performance-boosting planes mounted on your transom and controlled at the helm. If you already have and use trim tabs, you may not realize what retrofit options are available to you.

Keeping tabs on your tabs

Still growing in popularity, trim tab indicators actually show you the position of your trim tabs. They are not required to operate your trim tabs - you know your tabs are working by the boat's reaction to them - but many boaters still like to see that their tabs are moving and how far down they are deflected.

By having a trim tab indicator installed, you may start to recognize how far down you need to put your trim tabs to stay on plane in certain conditions. Keep in mind, the reason for tabs is to adjust for changing conditions in weather, water and weight - so no two boating days are ever exactly the same. But an indicator will help you get more familiar with how your tabs are working.


Your choice of indication comes down to personal preference. Every trim tab brand has its own style of indicator. There are some that are timer-based, and others, like Bennett's, that have sensors in the actuators to read actual trim tab movement.

For example, with Bennett, you can choose between an "all-in-one" control with LED indication included (Electronic Indicator Control), or a separate LED display (Tab Position Indicator) that you would add on to your existing rocker switch control. The Electronic Indicator Control has one extra feature - a built-in Auto Tab Retractor - that automatically retracts the tabs to "full-up" when your turn off the ignition. This helps you avoid any damage to the tabs during hauling, trailering and storage. The Auto Tab Retractor is also available as an add-on accessory to your trim tab system, easily connecting to your rocker switch control.

A third option, NMEA1, is a kit that connects through your NMEA backbone and allows you to see trim tab movement on your NMEA 2000-compatible multi-function gauge or GPS/Chartplotter. Check with your electronics manufacturer first to verify compatibility.

Cruise control for your boat

If you have trim tabs, you can appreciate how they help your boat run more efficiently and save you fuel. Yet no matter how well you control your tabs manually, in order to make all the minor adjustments that are possible - and gain the most fuel efficiency - you would need an electronic system that calculates and analyzes attitude readings more than a thousands times per second.

That's where an automatic control system comes in. Once you set it, it will constantly monitor your position and adjust your tabs to make sure you're always at the perfect attitude. It is most effective for cruising at a constant speed over long distances - those times when you just want to relax and enjoy the ride.

When you activate cruise control in your car, you select the speed you want to maintain and the car will remain at that speed until you press the pedals. In the same way, with your automatic tab control, you first set the optimum running attitude for your boat and save that into memory. Then when you turn it on, the automatic tab control will adjust the tabs for you to recreate that programmed attitude. It will do this until you choose to turn it off.

If your passengers move about the boat, causing a list, the automatic tab control will move the tabs and correct the list. If wind conditions create a bumpy ride, it will level out the boat, recreating the attitude setting you programmed.

An automatic tab control does not take place of your manual control. There are situations where you need to be in control of your tab operation. This includes "start-stop" boating where the boat operator needs to be in full control of the running attitude, and in any condition requiring a bow-high attitude.

Bennett's Auto Tab Control (ATC) can be installed on any Bennett system, regardless of what style control you have. A popular combination is to install the ATC with the Electronic Indicator Control - they easily plug together. Each of these electronics is designed to be a DIY installation and won't break the bank. With the fuel savings possible with ATC, it will ultimately pay for itself.

So if you're thinking about an upgrade to your boat, consider an indicator or auto tab control to get even more out of your trim tabs. Your boat - and wallet - will thank you for it!

Article courtesy of Bennett Marine, the largest manufacturer of trim tabs in the world. Check out the selection and special pricing for Bennett trim tabs.