Mercury Active Trim

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It was a few months ago when Mercury brought their new Active Trim innovation into South Africa and my charter boat Wizard, was one of the first to be fitted with the unit. The Mercury Active Trim comes in single or dual engine operation and can be used on any boat which is powered by Mercury F40 > 400 Outboard or Mercruiser Sterndrive engine. Basically, the Active Trim reads and talks to the engines, as well as other instruments in the boat such as the GPS. The Active Trim has 5 basic programs and I find these work well straight out of the box on the factory settings. Each setting can be fine-tuned to the skipper’s personal preference.

In the beginning you need to understand how the system works and experience the varying attitude effects on your boat. On the first trip with the Active Trim installed and engines trimmed in for take-off, I immediately realised the benefits of the system when my boat reached 4000 rpm and popped out of the water onto the plane without touching a thing. The best attitude for your boat when starting off is with the engines trimmed right in, this gives you maximum thrust for take-off. Thereafter one trims the boat’s bow up until the perfect ride is achieved for the current water conditions. In trimming a boat one is looking for a combination of comfort, safety and efficiency.

115hp TwinVee
115hp TwinVee

The Active Trim display has 5 orange lights that needs to be thought of as individual bow attitudes .. not numbers. So, the bottom number 1, is the bow down position and the top number 5 is the high bow position. I find that using the middle setting, number 3, is a good happy medium to start out the day with. All you need do then is press 2 or 4 once you’re on the plane to fine tune your boat. With experience I’ve found that I only use position 1 when I’m travelling head-on into big swell to give me a bow-down position to cut into the sea, and 5 when I’m running with a big swell and need to have the bow right up. The beauty of running a big swell with the Mercury system is that as soon as the boat starts to labour, the Active Trim makes the micro adjustments to keep the boat performing to its maximum. This clever feature responds by automatically trimming your engines in when needed and back out when it feels you’re running perfectly again. Unless you watch the engines you will not realise how much they being trimmed in this kind of situation. In essence what the system is doing is tucking your engines in the minute you begin to lose power in a trough to give you the thrust to power out, and then trimming out again once you are riding high. This in my book, is saving a fair amount of fuel in that you no longer press on the throttles to power out.

Age and experience are not always an advantage and with my over 4 decades of experience at the helm, I found it extremely difficult to relinquish control to the Active Trim system, much like letting your child drive you around for the first time. But as soon as you get used to the feel of what the system does and how it affects your boat, it becomes clear that the benefits are real and you begin to let it take increasing control. Peace of mind came from knowing that at any stage I could touch the trim buttons and regain full control. However, it must be remembered that this control is brief and the system will return to the attitude you selected after a few seconds, to take permanent control you simply press the off button.

Now that I have become familiar with the Active Trim system, I allow the system do most of the work throughout the day. For general running when conditions are moderate, the Active Trim system will take a huge load off your shoulders by constantly trimming your boat perfectly, and this will also save you fuel in the long run. When I encounter storm conditions, as we often do off Cape Point, I switch the Active Trim off and take full control of the boat, but maybe that’s just a head adjustment on my part. When I ride a storm, I constantly work the trims, throttle and wheel, often in varying amounts to counteract the changing conditions as they develop.

Mercury Marine Active Trim
Mercury Marine Active Trim

The benefit of the Active Trim system doing the work is that it frees the skipper up to be able to concentrate more on navigating, watching instruments and be more vigilant to the surroundings. I see a really positive use for speed boats and skiers in that once the skipper has set the perfect boat attitude, anyone less experienced can drive without fear. Now even the skipper gets a chance to ski if he chooses.

The Mercury Active Trim is a plug-andplay system that can be fitted in less than an hour, with cutting the helm, ensuring that your boat is not out of action for any extended length of time. I suggest putting the helm display within easy reach of your throttle hand. This offering should really be a standard fit on any boat as it adds so much safety and fuel saving benefits.

For more information on the Mercury Active Trim system contact your local Mercury dealer or use the contact form below.


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