[CA] [CA11] How Much "Wandering" is Acceptable on EV150

[GoodChance]

I'm having an ongoing "issue" with a newly installed EV150 (installed June 2018). It seems that I'm getting an awful lot of "wandering" in calm seas and river operation. I'll set the course to a known waypoint and the boat will wander by 5 to 6 degrees to port and then starboard (so a total of a 10-12 degree arc). Is this much wandering in flat seas acceptable? I should point out that the boat rarely deviates from a straight-line course by more than 50-75ft from point-to-point even when this course is 25-50 miles. So I'm pretty happy with this aspect but I wonder why the autopilot forces the boat to wander by 10 degrees.

All of the operating software on the AP is the most recent version (ACU is v2.23; Control head is v3.07). The calibrated max deviation on AP is 4.3 degrees. The compass is located in the console and not within 5ft of any ferrous materials.

I have lowered the "hard-over" time from a default of 10 seconds to 5 seconds. And I have played with the "dampening" features. The compass calibration was left "open" as opposed to "locked or closed".

The EV150 is networked to an a128. And if it means anything to you, there is also an a78 working as a slave to the a128. There is also a RD424 Digital radome connected to the a128.

The wandering used to be MUCH worse and was 20-30 degrees at one time. A Raymarine field technician visited the boat and we went for a short ride. He immediately saw the problem although he couldn't figure out what was the cause so we replaced the ACU, the pump and the compass. The wandering improved but I question whether the AP could be more efficient.

The boat is a 23ft Parker center console with a single Yamaha F250.

Your thoughts?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum GoodChance,

Unlike Auto mode, which is designed to maintain a specific heading, Track Mode will attempt to maintain the vessel within a corridor extending either side of the course line (Cross Track Error (XTE)). The width of this corridor will be based upon the autopilots Response Level setting. Having a properly functioning rudder reference transducer can also aid in the operation of this feature. As the function of the autopilot is to keep the vessel within aforementioned corridor, it is normal for the track to appear as an elongated S.

1) How close (number of degrees) are the Heading and COG data items when operating the autopilot at planing speeds in Auto (not Track) mode.
2) What is the autopilot's Response Level set to?
3) Has a rudder reference transducer been installed and interfaced to the ACU?
4) Is the system equipped to sense speed through water? If so, please configure the MFD to display the Speed data item, SOG data item, and XTE data item. When the symptom is observed, please respond with the observed values for these data items.
5) When operating in track mode over a 5 minute period what is the largest XTE observed after the autopilot has steadied the vessel onto the course?
6) Change the autopilot's Speed Input (MENU->SET-UP->AUTOPILOT CALIBRATION->VESSEL SETTINGS->SPEED INPUT) to SOG and then operate the autopilot in track mode at the same speed in which the symptoms were duplicated in step 4. When operating in track mode over a 5 minute period what is the largest XTE observed after the autopilot has steadied the vessel onto the course?

[GoodChance]

Thanks Chuck. I responded to each of your 6 questions/statements embedded within your original response as indicated above.

[Chuck - Raymarine - Moderator]

You're welcome.