20 ST4000+ Wheel & Tiller Autopilots: Owner’s Handbook3 Advanced Operation3.1 Using Track modeNote: You can only use Track mode if you have connected theST4000+ to a suitable navigation system providing SeaTalk orNMEA navigation information.The ST4000+ can receive track and cross track error informationfrom either:• a SeaTalk navigation instrument or chartplotter (see page 52 forinformation on connecting to SeaTalk)or• a non-SeaTalk navigation system transmitting data in theNMEA 0183 format – you can connect this directly to theST4000+ NMEA input (see page 53 for information onconnecting to NMEA equipment)In Track mode, the ST4000+ maintains a track between twowaypoints created on the navigation system. The autopilot computesany course changes to keep your boat on track, automaticallycompensating for tidal streams and leeway.Selecting Track modeTo select Track mode, press the track key with the autopilot in Automode.When you select Track mode, the autopilot can acquire a trackthrough either:• automatic acquisition (see below), when both cross track error(XTE) and bearing to waypoint (BTW) data are availableor• manual acquisition (see page 21), when only cross track errorinformation is availableAutomatic track acquisitionIf cross track error and bearing to waypoint information are bothavailable (via SeaTalk or NMEA), the autopilot can acquire a trackautomatically:1. Bring the boat within 0.1 nm of track.2. Press auto. The autopilot will display the current locked heading.3. Press track to enter Track mode.
