Posted: August 1, 2012
Is your system up to the challenge?When we had our full-displacement trawler, one of the issues we faced was how the boat handled in various sea conditions, including following seas, and how effectively the autopilot controlled the boat. Our experiences, and input from other full-displacement boat owners, have led me to a few conclusions.
While there remains some debate over the effectiveness of hull shape in the stern section of full-displacement boats, my research and time on the water show that most recreational, full-displacement boats will wander a few degrees to either side and at times may even squat down in severe following seas. We experienced a skewing effect of 15 or more degrees even with the autopilot on, which is common in these types of seas. Such sea conditions are where a properly configured autopilot can help make the journey safer and more comfortable and reduce crew fatigue.
While there are many reputable manufacturers of autopilots, our experience has been with the Simrad brand on our two Nordhavns. Both boats were configured with a single-system installation with dual controllers (one in the pilothouse and one on the flybridge). We enjoyed the safety aspect of having a backup controller, and we also had the rudder-indicator displays, which I found useful when maneuvering in tight quarters.
Selecting an autopilot system that is the right size for your boat is an important preplanning step that can save you time and money. These systems are expected to work long hours and do so in the worst weather. If the system is undersized or not robust, something is bound to fail at the worst time.
Here are a few things you can do to ensure your system reaches peak performance:
1. Talk to other owners of the same boat model and find out which settings they find useful.
2. Confirm that the autopilot pump, which steers the rudder, is the correct size. A simple method to confirm this is to move the rudder from hard-over on one side to the other side. You want the rudder to complete the move in a maximum of six seconds, to ensure it can keep up with sea conditions. An undersized pump will struggle to keep the boat on course, run hotter, resulting in breaking down the hydraulic fluid, and fail prematurely.
3. If your boat is equipped with active fin stabilizers, it is important to note that your autopilot will work harder as it compensates both for the sea conditions and the stabilizers.
4. Installing a complete dual system (heads, computers and pumps) not only provides the safety of a backup system but allows for dual settings for different weather conditions.
5. Even after you have selected the proper model for your boat type and size, you may want to break out the owner’s manual and read about fine-tuning the system for the sea condition you are in. Some units allow multiple settings to be stored for different running conditions (e.g., following, beam and head seas), making it push-button simple to obtain the optimum performance. Since beam seas will result in your autopilot working a little harder, fine-tuning the system over multiple trips makes sense. An important reminder is that one person’s desired setting may not be right for someone else; boat movement is to a degree a personal choice.