Using it well · 7 minute read
Autopilot steering modes
Understand autopilot steering modes: Auto heading hold, Wind, Track, Nav, No Drift and fishing patterns. Check required inputs and when to take manual control.
Most owners use Auto and nothing else, which is a pity, because the other modes are what make an autopilot a navigator rather than a heading-holder. Wind mode keeps the sails set. corrects for tide. holds a line over the ground across a set. Pattern modes fish. Each mode needs a data source and each behaves differently when you disengage, which is why instructors spend time on them.
Key facts
- Auto
- Holds a compass heading; needs only the sensor
- Wind
- Holds an apparent or true wind angle; needs a wind sensor
- Nav / Track
- Follows a route with cross-track correction; needs a plotter
- No Drift
- Holds a course over the ground; needs GPS
- Patterns
- Circles, zigzags, cloverleaf, orbit for fishing
Auto: heading hold
Auto holds the compass heading the boat was on when you engaged it. It knows nothing about tide, wind or where you are going. It is the right mode for motoring on flat water, for short legs, and for any time you want to hand-steer by pressing buttons. Course changes are made in one- and ten-degree steps on the head. In a current, Auto lets the boat drift sideways while pointing faithfully at the heading, which is how boats end up on the wrong side of a channel.
Wind mode: apparent and true wind steering
Wind mode holds an angle to the wind rather than a compass heading. Upwind, that means the sails stay trimmed as the wind shifts; the boat follows the lifts and headers. Downwind, it keeps the spinnaker full and stops the accidental gybe when the wind backs. The choice of apparent or matters: swings forward as the boat accelerates, so fast boats and anyone under spinnaker steer to true; slower boats upwind are fine on apparent.
B&G's bears away in a puff and comes back up as it eases. Raymarine's wind vane mode with dampens the roll-induced wander downwind. Both are worth setting up with someone who knows them. Wind mode is only as good as the wind data: a masthead unit that lags, or a poorly calibrated one, makes the pilot chase ghosts.
Wind shifts change your heading
Nav and Track: following a route
Nav (Navico), Track (Raymarine) and Route (Garmin) all mean the same thing: the plotter sends the pilot a bearing to the next waypoint and the cross-track error, and the pilot steers to stay on the line, correcting for tide and leeway. At each waypoint the pilot warns and, depending on setup, either waits for confirmation or turns automatically. Confirmation is the safer setting in traffic; automatic turning suits open water.
The mode is superb inside the Great Barrier Reef, in the Whitsunday Passage and in Moreton Bay's channels, and dangerous when a route is drawn carelessly through a sandbank or across a shipping lane. The pilot follows the line you drew.
No Drift: a line over the ground
holds a course over the ground from the moment you engage it, using GPS to cancel set. It is the mode for crossing a tidal stream to a specific point, such as the approach to Port Phillip Heads or across Backstairs Passage, without building a route. It behaves like Auto but corrects for current, which makes it many cruisers' default for coastal legs.
Tack, gybe and turn functions
Sailing pilots tack and gybe on command through a set angle at a set rate. On a shorthanded boat this is how one person tacks while the other handles the sheets. The rate should be set slow enough for the crew to keep up and fast enough not to stall. Practise it in daylight; a gybe under spinnaker driven by the pilot is a manoeuvre to rehearse, not to discover.
Pattern steering for fishing
Power-boat pilots offer circles, zigzags, cloverleafs, spirals, orbits and figure-eights, and some track a depth contour. They are for working a bait school, a drop-off or a wreck with hands free. Each pattern has a size and a direction; set them before engaging and keep a watch, because the pilot will orbit straight through another boat's drift.
What happens when you disengage
Pressing Standby in any mode returns the helm to you. Re-engaging Auto takes the current heading; re-engaging Wind takes the current wind angle; re-engaging Track resumes the route. On some systems Wind and Track are entered from Auto rather than directly, and on all of them a pilot resuming a route after a dodge will turn back towards the line, sometimes sharply. Learn the sequence on your own boat.
Questions
Frequently asked
Should I steer to true or apparent wind?
Apparent upwind on most boats; true downwind and on fast boats. Under spinnaker, true, always.
Why does Track mode turn sharply after I dodge?
It is returning to the route line, not just the bearing to the waypoint. Dodge with a wide margin or re-plan the leg.
Is No Drift the same as Track?
No Drift holds a course over the ground from where you engaged it. Track follows a planned route with waypoints. No Drift needs no route.
Do power-boat pilots have Wind mode?
Usually not, and it is not needed. Power pilots emphasise route following, No Drift and patterns.
Practise autopilot operation with an instructor
Habits are learned at the helm with someone watching. The training section explains what a good instructor covers and where to find one in your state.