Please select your home edition
Upffront 2020 Foredeck Club LEADERBOARD

Sailing Autopilot Systems - The Key Components

by Phil Anniss 30 Oct 17:00 GMT
Autopilot Systems are used on IMOCA yachts © nke marine electronics

For most cruising and offshore race sailboats, the autopilot is a critical piece of equipment. However, the difference between a "good" and a "not so good" sailing autopilot can be dramatic! Therefore, it is well worth understanding all the necessary components of a good system to create the autopilot package to suit your needs.

There is a lot more to a good sailing autopilot than simply a drive unit, computer and compass. To keep a steady course with variable wind and wave conditions requires many more sensory inputs. However, with today's computing power and accurate sensors - it is rapidly becoming possible for an autopilot to steer more efficiently than even an experienced race helmsman.

Over the last 10 years sailing autopilots have benefited from a large amount of R&D investment by the short-handed offshore race community, where this is a "critical success" system.

We can split a sailing autopilot system into two key instrument groups - Navigation and Pilot - but the Pilot system is built on top of a basic navigation system.


  • Navigation Processor (CPU)
    • The computer that brings all the sensor data together and interprets it and allows it to be displayed
  • Compass
    • Traditionally this has been a single-axis fluxgate compass but increasingly common, and significantly more accurate, is a 9-axis gyrocompass
    • In addition to heading they provide data on heel and pitch (adjusted for turn rate) plus acceleration
    • This improved boat motion data is a key element to improvements in sailing autopilot performance however it is dependent on having an up to date processor that can handle the complex calculations.
  • Wind sensor
    • Wind sensors can come in a range of sensitivities and accuracies
    • Again - accurate wind data together with the computational power to maintain real-time, clean, Apparent wind data can significantly improve autopilot performance.
  • Speed sensors
    • Traditionally speed sensors will be through-hull paddle wheels or flush fitting Ultrasonic sensors.
    • For the autopilot it is more the computation of acceleration that is important and increasingly there are alternative backup sources of this data i.e. GPS or accelerometers
  • Display
    • A key element of the Navigation system but not necessary for the pilot
  • Depth Sensor
    • Again, apart from having a back-up depth alarm (!), it is not required for the autopilot but a standard and essential element of your navigation electronics system.


  • Autopilot CPU
    • Combines the data from the navigation system with the rudder feedback sensor to operate the autopilot drive unit
  • Drive unit
    • There are many types of drive available on the market
    • Most are either linear drive systems attached to the tiller arm or direct drives connected directly with the rudder stock
    • They can be electric or hydraulic
  • Rudder feedback sensor
    • This is a key component of autopilot operation
    • Some autopilot drives incorporate this sensor in the body of the direct drive, which is much easier to setup
    • Tuning and maintaining the accuracy of a separate rudder angle sensor can be more challenging and a cause for loss of pilot performance over time.
  • Pilot control pad / remote
    • A basic but key autopilot component usually located next to the steering position but increasingly supplemented with a remote-control unit which can be worn around the skippers neck.

These are the key components of any autopilot system and if you have a clean sheet of paper it is relatively easy to decide on a preferred supplier and bring a complete plug&play system together. However, most owners are looking to upgrade, or work with legacy systems, and interfacing different systems to ensure compatibility is always a key consideration and usually requires some expert advice.


If you have only a basic navigation system, it is important to be aware that adding the best autopilot on the market will NOT necessarily provide a great result. It is the data coming from the navigation system and the quality of the wind, speed and compass sensors, together with the computational power of the CPU, that are key to overall sailing autopilot performance.

If you have any questions about sailing autopilots please contact us at via the Electronics Enquiry Form.

Related Articles

Continuous versus Discontinuous Standing Rigging
Looking at the differences, and pros/cons of both types Regardless of material choice (wire, rod or composite), there are two main types of lateral rigging configurations, referred to as Discontinuous or Continuous rigging. Posted today at 5:00 pm
Celebrating curves with the LOOP Flexi Stick-on
These padeyes can stick to a curved surface, and take a lot of weight You would probably agree that there are very few flat surfaces on a sailing yacht, whereas most hardware bases are flat. Using modern materials and construction methods, the innovative LOOP Flexi Stick-on padeye offers some interesting possibilities. Posted on 19 Nov
Straight Talking
Mast and standing rigging terminology from is all about performance sailing hardware and rigging systems. The heart, and driving force, of any sailing yacht is its mast and standing rigging which support the sails. In this article we outline the key terminology. Posted on 12 Nov
Composite Standing Rigging
Material options discussed by Having established the significant advantages of reducing rigging weight, next we would like to look at the composite rigging options available on the market. However, before we get to that point, we need to take a little diversion. Posted on 5 Nov
Composite rigging benefits
A 75% weight saving can transform performance is constantly striving for lighter, faster and safer sailing for all boat owners, regardless of sailing style. Composite (or synthetic) rigging is one of the biggest and most cost-effective performance improvements that you can make. Posted on 22 Oct
Torsional Ropes Versus Cables
Noting the all-important point at which you should change between them In this blog we explore the differences between Torsional Ropes and Custom Torsional Cables, the pros and cons of each and provide guidance on the specification boundaries between the two. Posted on 16 Oct
Adding a Staysail?
Inner forestay setup options discussed by Are you considering upgrading your sail plan to include a staysail? It is an increasingly popular choice, offering considerable performance benefits. In this article we focus on the various setup options. Posted on 8 Oct
Improve Your Sailing Performance
Three simple, cost-effective upgrades from Reducing weight should be every sailors goal, no matter what their sailing style. One kilogram removed from the mast and rigging package is equivalent to adding 4kg to the keel. So, reducing weight aloft increases your stability. Posted on 1 Oct
Stripping and recovering yacht ropes look at when, where and why The majority of yacht ropes are double braid construction i.e. with a core and braided cover. The purpose of this cover is to protect the core from general chafe, abrasion and UV damage but also to provide grip. Posted on 23 Sep