Autopilots for boats
- What does an autopilot do? -
An autopilot is an automatic steering device for boats. In other words, an autopilot allows your ship to be steered automatically. From different data sources, this steering system / course computer calculates the course and intervenes if necessary. Most pilots work via compass or GPS. Additionally, you can use external NMEA2000 data sources such as wind sensors to optimise the autopilot's course or steer it according to the wind. Whether you are going on a long trip, racing or looking for a suitable autopilot for a relaxed afternoon cruise, through the knowledge of our experts and our comprehensive product range, you will quickly find the right autopilot for your boat or the right autopilot spare part.
Which autopilots are out there and what should be considered when choosing?
The following types of autopilot are generally available:
How to choose the right autopilot:
Each autopilot type has its own advantages and disadvantages. When choosing an autopilot, it is important that you base your calculations on realistic data from your boat. Does your boat really have a displacement of 11 tons or is it more like 13 tons when fully loaded? Often the actual displacement of a fully loaded boat is a good 20% above the stated displacement. Whether your boat is heavy or light at the rudder also plays a role. This information is extremely important when selecting an autopilot system, because it won't help if you go for a cheaper option and the autopilot's drive mechanism cannot move the rudder blade from light to hard in a reasonable time or stops after some time due to overload. However, you should not choose a drive that is too large, as this could cause your boat to react too strongly to course corrections and start to rock. You should therefore choose an autopilot drive suitable for your boat and with the right capacity.
Using cockpit pilots
If you intend to use your autopilot only during good weather and in light swells then you can safely go for a RAYMARINE ST series
tiller pilot, SIMRAD TP
series tiller pilot or RAYMARINE
wheel pilot. Please note that these autopilots do not have powerful drives due to their design and are therefore not very efficient in heavy waves and rough seas. Choose your autopilot according to the displacement of your boat when it is fully loaded and allow for some margin.
Using inboard autopilots
If, on the other hand, you do not want to forego your autopilot even in bad weather conditions, or if you want to kit out your boat for a long journey or a round the world trip, then we strongly recommend the installation of an inboard autopilot. The drives of these autopilots are designed for continuous operation and are usually much more powerful. For example, hydraulic linear drives provide a maximum thrust of up to 1.2 tons and easily keep boats with a displacement of up to 35 tons on course. Depending on the existing steering system, hydraulic, electromechanical or for chain steering systems, so-called rotary drives or geared motors are available.
Choosing the right autopilot drive and course computer depends on the existing steering system, the actual displacement of your boat and whether your boat is heavy or light at the rudder. For hydraulic steering systems, you may be able to continue to use the existing hydraulic pump, you only need the appropriate course computer and accessories. Which course computer you need depends on the amperage (A) of your existing pump or drive. If you need a new hydraulic pump, choose one according to the volume of the existing hydraulic cylinder and then choose the course computer appropriate to the hydraulic pump. Make sure that the whole hydraulic system is proportioned correctly in accordance with the rudder pressure.
What types of drive are available for autopilots?
The rudder is moved by means of a hydraulic pump and a hydraulic cylinder. The size of the hydraulic pump depends on the volume of the hydraulic cylinder. Special continuous-operation pumps are available for large cylinder types up to about 1200ccm. Information about the volume of the hydraulic cylinder can be found in the manual or on the cylinder itself. The size of the hydraulic pump determines which autopilot to choose. Make sure that the autopilot is able to operate the hydraulic pump.
Hydraulic linear drives
Hydraulic linear drives are designed for use on larger, mechanically steered ships and can easily guide a ship with a displacement of up to 35 tons. Since hydraulic linear drives require a lot of power, an autopilot with a high switching power is required in most cases. Make sure that the autopilot is able to operate the hydraulic pump.
Mechanical linear drives
Mechanical linear drives are the most commonly used drives on sailing yachts. This is because they deliver high thrust of up to 20 tonnes in a relatively compact design. By mounting below deck, these drives move the rudder directly from the tiller arm or rudder quadrant. It is important that the installation of the mechanical linear drives is carried out professionally. It is essential that the drive is firmly fixed to the hull of the vessel, and there is often a need to reinforcce or adapt the location where the ram base is fixed, because otherwise the drive will break away from its fixings at high thrust.
Mechanical linear drives are available in different sizes. Make sure that the autopilot computer is able to operate the hydraulic pump.
Mechanical Rotary Drives
Rotary drives, are used on motor and sailing boats with cable or push rod control and a displacement of up to 20 tons. With this steering system the rudder is moved by a chain and a gear wheel. It may be necessary to adapt the on-board control system to integrate the rotory drive.
Rotary drives are available in different sizes. Make sure that the autopilot is able to operate the hydraulic pump.
Outboard with cable steering
This type of drive provides automatic steering for outboard engines with Morse 290, 304411 and Teleflex SSC52 cable steering. Installing the drive is usually quick and easy, the steering control cable is routed through the drive and the drive is mounted directly behind the steering wheel.
It is possible to install an autopilot appropriately dimensioned for your Z-drive. This is connected directly to the Z-drive. Make sure that the drive and the autopilot are compatible. In this respect, there are differences depending on the manufacturer of the Z-drive. Please contact us or the manufacturer before purchase.
What does an autopilot system comprise?
An autopilot system basically consists of a drive, a compass, a course computer and a control unit. On tiller pilots like the RAYMARINE ST series
and SIMRAD TP series
, all these components are built into one housing. For inboard pilots, all these components are installed individually.
The course computer and the compass sensor are the central system of the autopilot. Modern heading sensors are much more than a simple direction indicator. In addition to the current course, ship movements in all directions are measured and used to optimally calculate the necessary rudder movement. Be sure to follow the installation instructions in the compass sensor manual and select the installation location accordingly. While with older compass sensors it was possible to hear a rattling sound when moving the sensor quickly, modern sensors no longer contain moving parts, but work with solid-state technology.
In addition, an autopilot control unit is usually included in the autopilot system for inboard autopilots. Some systems allow you to integrate a wireless handheld remote control
or a chart plotter or multifunction device
. A rudder position sensor
is not required for all autopilot systems and is therefore not included as standard with all manufacturers.
How can the autopilot be calibrated and is a rudder position sensor necessary?
Modern autopilot systems no longer require calibration by default. In order to determine deviation and steering response, the autopilot sensor measures all relevant data while the vessel is in motion and virtually calibrates itself. Once you are satisfied with the autopilot's steering response, some autopilot systems allow you to disable automatic calibration of the autopilot system.
Modern autopilots are able to determine the position of the rudder by manually calibrating the rudder position once. However, the position of the rudder can be determined much faster and more accurately with the aid of a rudder angle sensor
, and some display devices can only show the current rudder position in conjunction with appropriate rudder angle sensors.
How do you operate an autopilot?
An autopilot is usually operated using a special autopilot control panel, although in most cases tiller pilots are operated using the buttons on the tiller pilots themselves.
A special autopilot display
, usually found on inboard pilots, allows you to set and correct course, make adjustments, and turn the autopilot on or off. Modern autopilots can also be controlled with a compatible chart plotter or multifunction display
. It is possible to send waypoints and routes via a chart plotter to the autopilot or to correct the course. This means that the autopilot control unit can be fully replaced by a compatible chart plotter. However, we strongly recommend that you continue to use your own autopilot control panel, as this display gives you constant and above all quick access to the autopilot functions. If, for example, you need to disconnect the autopilot quickly in a dangerous situation, or set it to standby in order to operate the rudder yourself, you will first have to tediously activate the standby function on the chartplotter, whereas there is an extra standby button on the autopilot control unit, which can be pressed quickly in an emergency.
Autopilots can also be operated via a radio remote control
. Operation is largely limited to course corrections and switching to standby mode, but important data such as current speed, depth or course can also be displayed on some models.
What general control modes are there?
Autopilots generally have the following control modes:
As the name suggests, the autopilot follows a fixed course using compass steering. This mode is the most common way to use an autopilot and it is a reliable way to steer, especially for long distance trips. The boat is set to the desired heading and this is maintained by the autopilot through permanent course corrections.
When steering to a waypoint or route, the autopilot maintains the course needed to reach the set destination, the waypoint. This means that the autopilot constantly adjusts its course to the current destination.