Autopilot turning too early for track course

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Steven,

Q1. With this configuration, should speed input be set to SOG or to the STW provided by the DST110?

A1. Should the autopilot be interfaced to a properly calibrated and correctly functioning source of speed through water (STW), then it would be recommended that the autopilot be configured to use speed through water rather than speed over ground (SOG) as its speed data source. Proper operation of the STW sensor may be checked by operating the vessel under slack current conditions and then verifying that STW and SOG are close in value. Use of STW rather than SOG will permit the highest level of autopilot performance, particularly for slower moving vessels which may be operating under conditions of leeway (current and wind).

Q2. Is this the cause of advancing too early?
A2. Negative. Waypoint arrival is determined by a configuration setting within the navigational product (ex. MFD, GPS display, computer running navigational software application, etc.) which has been interfaced to the autopilot. Within the settings of most navigational products, a setting is available for specifying the radius of the arrival circle around a waypoint/cursor position which is being navigated to. The default arrival circle radius setting for Raymarine navigational products is 0.1nm (approx. 600'). For owners of a/c/e/eS/gS-Series MFDs operating with the final release of LightHouse II software (v19.03), the command sequence which will permit the operator to configure this setting is HOME->SET-UP->ALARMS->SETTINGS->SAFETY ALARMS->WAYPOINT ARRIVAL->WAYPOINT ARRIVAL RADIUS.