Ev-200 S-turns

[Chuck - Raymarine - Moderator]

Jeff,

Troubleshooting should begin by ensuring that the autopilot's EV-1 Sensor Core, ACU, and p70/p70R have each been updated with the latest available Raymarine product software updates. Following the latest software update, care must be taken to ensure that the autopilot was reset (not to be confused with resetting the control head), Dockside Wizard executed, and cruise to establish deviation table / vessel handling characteristics performed.

Afterwards, should S-ing occur, then it is recommended that the system's speed through water sensor (if equipped) calculated Speed be compared to SOG to ensure that these values are close. If not, then the Speed through water sensor should be calibrated to match SOG at the speed at which the autopilot is typically executed. Should a fault with the Speed through water sensor be identified, then the autopilot should be configured to use SOG instead of Speed until the Speed through water sensor has been fixed/replaced.

Finally, performance of autopilots will be maximized when interfaced to a rudder reference transducer. Is your autopilot interfaced to a rudder reference transducer ... tested by placing the autopilot in Standby mode and then rotating the vessel's wheel or moving the vessel's tiller. Should the rudder bar shown on the autopilot control head indicate corresponding rudder movement when in Standby mode, then a rudder reference transducer has been interfaced to the autopilot.

Finally, it is normal for an autopilot to "S" to a degree when operating in Track mode, as the function of track mode is to maintain the vessel within an imaginary corridor running from the departure point to the waypoint/cursor locations and whose width is determined by the setting the Response Level setting. Configuring the Response Level to the Performance setting will maintain the smallest corridor width and tightest course handling (smallest magnitude "S"), while the Leisure setting will permit the largest corridor width and slower response to rejoining the course (largest magnitude "S").