Autopilots 101

Published in Northwest Yachting Magazine - May 6, 2020

Autopilots 101

Once considered nice-to-have, autopilots are now readily available for after-market installation on the majority of boats.  As with most marine electronics, the price has come down, and the level of sophistication and value to everyday boaters has gone way up. The two most significant improvements are rate motion sensors and the ease of calibration. Older autopilots used a fluxgate compass heading; however, the new units have a rate motion sensor that understands pitch, yawl, and the rate of turn, making travel in confused seas less stressful on the auto-pilot. The new autopilots are also much easier to calibrate and even have the ability to learn and tune themselves for your particular boat and auto-learn numerous sea states. Some models, like the Garmin with Shadow Drive, allow you to grab the wheel to disengage the autopilot and it knows when you let go and it re-engages.

Another advantage is the interoperability between navigation systems and the advances in reducing the power consumption of these units. Autopilots are now available in several different sizes based on your type of boat, displacement, and steering system.

What are the main advantages of installing an autopilot? Number one is when you steer true to a set course; you save time and fuel. With all the strong currents in the Pacific Northwest, we rarely go where the boat is pointed; in other words, the heading of the boat and the course over ground aren’t always the same. You also have the ability to leave the helm to trim sails, adjust lines, take a break from holding the helm steady, watch for logs or make a radio call, especially if you are single-handing. If there is an emergency on board, an autopilot serves as an extra crew member. For off-shore sailors, helm fatigue can lead to poor judgment and slow reactions. If you travel at night or in severe low-light conditions, it can be challenging to steer to a point on land or magnetic compass at the helm; an autopilot can keep your boat on a specific course without straying.

There are three different types of autopilots. Windvane or self-steering is an older type of autopilot that transfers wind energy from a vertical air paddle to a trim tab or a water paddle attached to the rudder. The newer, more common autopilots are Above Deck and Below Deck. Above Deck are more common on smaller boats, generally under 35 feet. These autopilots are inexpensive, easy to operate, and energy-efficient. They connect either to the tiller or directly to the steering wheel and are powered by a small motor. Below Deck are generally best- suited for over 30 feet and larger displacement boats. The main components of an autopilot system are the course computer or central processing unit with a smart heading compass, a drive unit which can be a hydraulic pump, a linear drive or rotary and a control head used to interface with the autopilot system.

Depending on the type of autopilot you install, there are a number of different operating modes. The default is compass mode; it will steer the compass course shown on the control head and will stay on the same course, over time.  Navigation mode allows you to chart a course and move to a waypoint or route mode, which is a collection of waypoints. When following a route, as you reach each waypoint, you will be notified and prompted to proceed to the next waypoint.

The wind or wind vane mode allows your chartplotter to see the wind and steer to it in the same way you would manually. This is typically used for open water or long ocean trips.

Another recommendation is to have a remote control. Urging boaters to err on the side of safety, we don’t recommend boaters use a remote control as the primary interface for a second station. Anything wireless can fail because of connectivity issues or even a weak battery; in our opinion, it’s not worth the risk of not being able to disengage the autopilot at a moment’s notice. As such, we strongly encourage operators to have a control head at each helm in case you have to quickly disengage the autopilot. The autopilot remote control is better suited as an add-on that is used away from the helm.

Most installations are multi-day and are recommended as an advanced/expert do-it-yourself project only. The autopilot integrates with your steering system, and the consequences of losing one of the most critical systems on your boat are too high. If you chose to install it on your own, make sure you are extremely confident with your skills.  Autopilots also include some cool functions such as rudder angle, so you always know which way your rudder is facing. You can also install a repeater screen that relays the course headings in your bunk or galley.

If you haven’t considered an autopilot before, it may be time. Gone are the days of locking your wheel or tiller in a straight line.


About the author: Jeff Cote is a systems design engineer and owner of Pacific Yacht Systems, a full service shop delivering marine electrical and navigation solutions for recreational boats. Visit their website and blog for info and articles on marine electrical systems, projects and more: www.pysystems.ca.

 

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