Please select your home edition
Upffront 2020 Foredeck Club LEADERBOARD

Sailing Autopilot Systems - The Key Components

by Phil Anniss 30 Oct 2020 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

Mantagua's Certified NAVIPRO Navigation Lights
Products enabling lighter, faster and safer sailing from Lighter, faster and safer sailing is our mantra. Thus, we're excited to launch our new product category - Navigation Lights - on, to keep you safe at sea. Posted on 6 May
Karver KF V3 Furler Accessories Guide help you identify what will fit best into your set-up The Karver KF V3 range is now available at and with this latest iteration of their popular KF furlers, Karver have moved away from dedicated top-down drums in favour of a more flexible modular system. Posted on 29 Apr
The LOOP Boa Constrictor Clutch
Maximise your deck space - build vertically! Deck space is prime real estate on a sailboat, with clutches and jammers vying for space, often on narrow areas such as the cabin top or mast. So what do you do if you can't fit any more clutches to your deck? Build vertically! Posted on 22 Apr
Horizontal, Vertical or Compact Motor?
Electric sailboat winch options examined by You've chosen to upgrade from a manual winch to an electric winch. Now, you need to decide on motor placement. This is a critical design decision which largely depends on your boat's available space below deck. Posted on 15 Apr
MORFRAC and 3D Printing
A success story, investigated by In recent years, 3D printing has revolutionised manufacturing processes. Expiring patents have caused 3D printing costs to plunge and quality to soar, granting opportunities for small-scale manufacturers to experiment - and excel - with 3D printing. Posted on 9 Apr
Lewmar EVO Winches - Made to Last
Flagship winch range is an evolution of 'the most popular winch ever made' Lewmar's flagship EVO® winch range is an evolution of their Ocean range which they claim is the most popular winch ever made. This is due to their widespread use by volume boat builders who prioritise ease of use / maintenance and reliability. Posted on 2 Apr
A Truly Unique Proposition
Karver winches seamlessly change between 4 gears without any switch Karver are relatively new to the world of sailboat winches but they are bringing something completely different to the market. Their KSW Speed and KPW Power winch ranges can offer some dramatic advantages. Posted on 25 Mar
What size electric sailboat winch do I need? consider application and load When choosing an electric winch, there are four main factors to consider: speed (1, 2 or 3), motor placement, drum material and size. In this article, we'll focus on size. Posted on 18 Mar
The nke Multidisplay
All your boat data in one place GPS, navigation data, wind data, boat speed, heel, rig loads etc. Onboard electronics are far more accurate and capable than ever before, so sailors are able to charge and depend on more electronic systems. Posted on 11 Mar
Andersen's Electric Winch Range
Quality cruising with elegant, stainless steel winches that last a lifetime Andersen Winches are iconic. Often considered the benchmark for quality, Andersen's elegant, stainless steel winches take pride of place on the foredeck. Underneath the stainless steel exterior, an internal construction manufactured from aluminium bronze. Posted on 4 Mar