[CA] [CA11] Speed input

[George Bailey]

My EVO autopilot seems to work better having set the Speed Input to SOG. What is the downside to using this setting instead of speed through the water? What issues might I see? Thanks.

[Chuck - Raymarine - Moderator]

Welcome back to the Raymarine Forum George,

Within a system featuring a properly functioning and calibrated speed through water (STW) sensor (configure the system to display Speed and SOG ... these should be very close in value in the absences of leeway forces), STW will typically permit the greatest level of autopilot performance ... particularly in seas or when experiencing leeway forces (current and wind). However, should STW sensor not be functioning properly and/or not be properly calibrated and should STW be selected as the speed source for the Evolution autopilot, then the autopilot's performance will typically be adversely affected.