Ask Andrew: On the Level
One of the thrills of boating is the process of becoming intimately familiar with your boat. The sound the wind makes as it hits your standing rigging, the number of turns of the wheel, the pressure on the throttle, and the tilt of the trim tabs.
July 26, 2023
the helm display – brightly lit, comfortable and colour coded
One of the thrills of boating is the process of becoming intimately familiar with your boat. The sound the wind makes as it hits your standing rigging, the number of turns of the wheel, the pressure on the throttle, and the tilt of the trim tabs. Part of getting to know your boat and achieving maximum performance is how the helm responds under different conditions.
Recently, I was asked to install an auto-trim system. I had previously read an article on the technology but assumed (wrongly) that it would be a highly complicated installation, involving new tabs and hydraulic components. In the end it was much simpler to install than I’d imagined; and performs better than expected, too.
I started with a basic set-up: two hydraulic trim tabs moved by a hydraulic pump, controlled by two simple helm switches labelled ‘bow up’ and ‘bow down’. The boat’s owner was looking for a solution to help with stability, ease of use, and fuel efficiency – but without constant adjustment.
the ACU – easy to mount, plug-and-play, and only the size of your hand
The system is plug-and-play and can be installed in several different configurations. In the set-up that I was working with, the installation was quite straightforward:
– the helm switches were replaced with a new led-lit display pad. This pad can allow manual control or can simply display a current trim tab state. It also allows pre-sets and ‘favourites’, allowing the operator to set their own boating style or customization.
– An Actuator Control Unit (ACU) is installed next to the hydraulic pump. This ACU has a built-in gyro to allow it to understand how the boat sits level, and how the trim changes during acceleration. The ACU is calibrated during set-up through a couple of simple steps.
– The new helm display is plugged into the ACU, and the ACU is plugged directly into the hydraulic pump.
an entire set-up including wiring, designed to marry-up to an existing trim-tab system.
In more complex installations, extra wires and adaptors are available to connect the ACU to the trim tab sensors (if available), and the NMEA network (if available), allowing more accurate trim-tab settings, and the addition of GPS and chart plotter information. On modern Multi-function displays, the ACU can be tied in so that the trim tabs can be controlled on one screen.
Once all the plug-an-play connections are made, an in-water calibration in 3 steps is required:
1) Measuring the boat at rest to set the gyro.
2) Measuring acceleration and the change in list and bow angle based on full throttle acceleration.
3) Set up of presets on the control pad.
The helm control, ACU and adaptor cables come in one kit, and retails for $1350. Installation can be done by a handy boat-owner with a minimal number of tools. The simple installation that I took on took about three hours from start to finish.
Including an auto trim system aboard your boat can yield a number of benefits:
A) The guesswork is taken out of trim adjustments – the ACU does all the work for you
B) More comfort – both when moving quickly, and when cruising, to adjust the boat’s ‘level’ despite extra people or stuff aboard (or moving around aboard as the boat is underway).
C) Greater fuel economy without having to work hard for it.
All-in-all, I consider this a great investment – for real dollars, as well as ease of use, and added comfort.
Andrew McDonald is the owner of Lakeside Marine Services – a boat repair/maintenance firm based in Toronto. Andrew has worked in the marine industry for 12 years and is a graduate of the Georgian College ‘Mechanical Techniques – Marine Engine Mechanic’ program.
Questions or comments for Andrew? Email him directly via: askandrew@lakesidemarineservices.ca
