Tuning an autopilot can be complicated, but it's vital to get the best out of your pilot in terms of control and power consumption. Pip Hare offers her expert tips
The latest generation of autopilots require less manual input to perform well but, besides selecting the correct mode (read Pip Hare‘s piece on how to make the most of your autopilot), there are other ways to go about tuning an autopilot for optimum comfort and speed.
Manufacturers have rolled the basic adjustments into ‘umbrella settings’ to allow ‘one touch’ tuning – some pilots (such as the H5000 from B&G) are even able to change settings automatically if the boat is struggling to hold its course.
However, many of us will still be sailing boats with older systems and even the best autopilots sometimes require a bit of human intervention.
Although the individual settings may be hidden on new pilots they can generally be found and adjusted in the deeper menus of a system so it is worth having a poke around and understanding what can still be manually changed.
Tuning an autopilot: response
The response level determines how often your pilot makes course corrections. Response should be a setting you change often, aiming for your pilot to use the minimum response level to keep a good course in any given conditions.
As the sea state or wind angle changes, just as a human being will modify their helming style, the autopilot response level will need to be changed.
A higher response setting should deliver tighter course-keeping but will require greater power consumption and can result in an uncomfortable ride for your crew so remember to adjust the performance down as well as up.
Gain is the function that controls the size of each rudder movement. This is a setting that may not be found on more modern pilots as manufacturers tend to incorporate the gain into the umbrella response settings so they both change together.
If working with a pilot that still has a separate gain then use it to tune the aggression of the rudder movements. I’d recommend lower gain and higher response for sailing upwind (small but frequent movements of the helm) with higher gain and lower response sailing downwind (large movements of the helm but fewer of them). Big wind and big seas reaching or downwind will require high gain and response.
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Don’t forget to check sail trim if you are needing to boost either response or gain, especially when reaching or sailing upwind. Take the helm and feel the balance of the boat – it may be that you need to take in a reef or ease the vang rather than adjust the pilot settings.
Counter rudder is the setting that determines how much opposite rudder is applied to slow down the rate of turn as your pilot returns to its set course.
In everyday conditions with modern pilots, counter rudder is not a setting that will need to be trimmed and it will be incorporated into an ‘umbrella’ response setting as with gain. However, there are conditions when the ‘factory’ counter rudder settings will not work and you may need to manually adjust.
Increase your counter rudder settings if the pilot is weaving across your rhumbline. This can often be required in cross seas or big swell downwind. If you do manually adjust counter rudder, don’t forget to drop it back down again as conditions diminish: if your pilot is making short, jerky course alterations the counter rudder is probably too high.
The wind response is a bit like rudder response. It’s used when the pilot is steering in wind mode and determines how tightly the pilot will keep to any given wind angle.
Sailing upwind with a well-balanced sail plan, your wind response could be set quite low; downwind sailing under spinnaker may require a higher response rate. If conditions become shifty you may also need to increase your wind response. Remember the higher the response the more uncomfortable the ride and the more power you will use.
When trimming your pilot for wind response you must also consider your sail trim – the two things are intrinsically linked. If the pilot is struggling to hold a particular wind angle then don’t go straight for an increase in response.
Take the helm first and feel the amount of weather or lee helm on your rudder. If conditions are gusty or shifty sailing upwind try increasing the twist in your sails, move the jib cars back and the mainsail traveller up and ease sheets a little. This will allow the boat to carry on driving through a great range of wind angles so the pilot will not need to be as ‘snappy’.
You may see a little luffing at the front of each sail when you are pointing at your highest but so long as the back of each sail is still driving the boat will keep powering forwards. This mode of sailing will be a little slower overall but it will be more comfortable and the pilot will require less energy, so think about what your overall objectives are. If you are not racing then comfort and power consumption may be more important.
This is a setting that can be found on older pilots and will help achieve better results in gusty conditions. Whereas wind response dictates how closely the autopilot will keep to a given wind angle, wind damping controls the amount of data that is being fed into the autopilot computer; increasing the wind damping will reduce the flow of data. This can be a particularly useful tool in sea states with a short wave length, or light airs with residual swell.
If the mast head is moving around a lot, the wind instruments will be registering greater variations caused by the movement of the boat and not necessarily changes in the wind so damping down the data flow can help.
Of course, the other option for these conditions is to switch to compass mode.
Not all pilots have gust response – or surf response/surf mode – options, but if yours does then I would 100% recommend you get to know it and use it. These settings can be activated when the boat is steering in wind mode and will enable the pilot to react automatically to changes in the apparent wind caused by gusts or large increase or decrease in boat speed.
Gust and surf modes are used downwind and allow a boat that is steering to a true wind angle to bear away as the apparent wind comes forward in a gust or a surf and then head back up again as the apparent wind goes back aft. Most often these settings will need to be enabled, and then can be tuned to determine how aggressive the response will be. This will be an extra layer of response over and above wind response, so if gust/surf response is required, I’d expect a pilot to be already steering to a higher wind response setting.
Once this mode is enabled you can choose how aggressively the pilot responds to each change. Some pilots’ gust modes can be set to activate automatically if steering in wind mode between two prescribed wind angles.
Trim your pilot
This is far from an exhaustive guide to pilot controls but hopefully should provide a good grounding for some of the base settings. The pilots I use when racing solo offshore are now capable of incredible levels of response to a huge range of data inputs.
Whatever your pilot set up there is no getting away from the fact that the more you know about it the better it will perform.
Every boat is different, and every time you go sailing the conditions, sail trim and sea state will require a slightly different style of course keeping.
An evening spent with your nose in the long form manual, working your way through all of the menus on your control head will pay dividends in battery management, comfort and speed on any longer passages.
While passagemaking, take notes of what works and build your own pilot trimming guide to reflect changing conditions so everyone on board can make the most of this incredible, uncomplaining crewmember.
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