[DG] [DG11] EV-1 “oversteering”

[ritchardfindlay]

I installed a new EV-1 with wheel pilot a few months ago on a 14,000 lb sailboat. When you use it, it tends to oversteer all the time, or work all the time, never stopping. It is so busy that today in a modest following sea it turned the boat into a seesaw, rolling back and forth. Not just uncomfortable, but the unit is working so hard to keep a course.

I have tried all 3 preference settings on the P70 head, and all have the same habit. Did I goof up the calibration?

My old ST 60 had multiple adjustments, this one just one simplistic one.

What to do?

[Derek - Raymarine - Moderator]

Hi ritchardfindlay
Thank you for your enquiry.

You do not mention but do you have cable steering or hydraulic? How many turns of the wheel do you have from Hard Port to Hard Starboard?

From your description it sounds like the autopilot is constantly operating backwards and forwards? If this is the case, then there are some things to check out.

Is the EV1 heading sensor close to anything ferrous or magnetic? Go into the Diagnostics menu on the p70 and scroll down through the settings in the control head, ( in the ABOUT Display or About Pilot menu in the DIAGNOSTICS menu) If you scroll down to the bottom of the About [censored] page, then you will see the deviation recorded when the EV1 was calibrated, if it is more than 10-15 then it is likely there is magnetic interference affecting the pilot - which will lead to oversensitivity and poor steering.

Other things to check are the steering system itself, is there free play that is affecting the rudder positioning or is the steering very sensitive to small movements?

You might also try changing the vessel hull types, the EV100 has different characteristics programmed for different hull types and sometimes an unexpected selection suits a particular hull and rig type better, for example Sail SLOW TURN can make a big difference.

Is there a rudder reference unit fitted in the system? if not, then this may be an option - some boats will benefit from adding the rudder reference unit due to their specific handling or hull characteristics.

Please note that you can access more levels of calibration by making sure that the CALIBRATION LOCK is turned OFF, this will enable you to make further changes to calibration, for example, you can also reduce these repetitive wheel movements through rudder damping - if there is slop or free play in the steering mechanism, then try to increase the RUDDER DAMPING in the DRIVE SETTINGS menu in AUTOPILOT CALIBRATION.

I hope these suggestions help?
Regards
Derek

[Derek - Raymarine - Moderator]

Hi ritchardfindlay
Thank you for your enquiry.

You do not mention but do you have cable steering or hydraulic? How many turns of the wheel do you have from Hard Port to Hard Starboard?

From your description it sounds like the autopilot is constantly operating backwards and forwards? If this is the case, then there are some things to check out.

Is the EV1 heading sensor close to anything ferrous or magnetic? Go into the Diagnostics menu on the p70 and scroll down through the settings in the control head, ( in the ABOUT Display or About Pilot menu in the DIAGNOSTICS menu) If you scroll down to the bottom of the About [censored] page, then you will see the deviation recorded when the EV1 was calibrated, if it is more than 10-15 then it is likely there is magnetic interference affecting the pilot - which will lead to oversensitivity and poor steering.

Other things to check are the steering system itself, is there free play that is affecting the rudder positioning or is the steering very sensitive to small movements?

You might also try changing the vessel hull types, the EV100 has different characteristics programmed for different hull types and sometimes an unexpected selection suits a particular hull and rig type better, for example Sail SLOW TURN can make a big difference.

Is there a rudder reference unit fitted in the system? if not, then this may be an option - some boats will benefit from adding the rudder reference unit due to their specific handling or hull characteristics.

Please note that you can access more levels of calibration by making sure that the CALIBRATION LOCK is turned OFF, this will enable you to make further changes to calibration, for example, you can also reduce these repetitive wheel movements through rudder damping - if there is slop or free play in the steering mechanism, then try to increase the RUDDER DAMPING in the DRIVE SETTINGS menu in AUTOPILOT CALIBRATION.

I hope these suggestions help?
Regards
Derek