[TG] [TG11] EV1 takes vessel off course

[ajhaddow]

I bought the EV1 system late 2014 & has been working perfectly.
Last week while sailing my yacht we ran aground while I was downstairs.
I had the autopilot set to AUTO & somehow the system turned me off course in 10 min. into a sand bank.
Once I got off I put the pilot on AUTO & after 5 sec the wheel turned to starboard perhaps 5 deg, then 10 deg to port then 15 deg to starboard then 20 deg to port where I put the pilot on standby.
I did all the re-setting in the P70 including re-set compass to no avail.
I noticed there was a message at the bottom of the P70 stating DETECTING MAGNETICS with a slider - was mostly red – this keeps repeating & never finalised – I don't remember seeing this before.
The pilot was working perfectly 2 weeks previous. Absolutely nothing has changed.
Today I did a FACTORY RESET on the P70 & spent time setting up the P70. The DETECTING MAGNETICS did complete although it took a good 1/2hr while moving the yacht about.
The P70 uses the GPS from the E7. I even borrowed a new Raymarine RS150 GPS & connected to the network with no difference.
Any idea what has gone wrong. The P70 is reporting correctly all units it can see – e.g. chart plotter, compass, ACU-100, VHF radio & AIS. Speed is set to GPS on the P70.
The E7 is using V19.003, & hardware V3.
ACU100 is using V2.23 (RSCP V1 L4)
EV1 Course Computer (compass) is using V2.18 (RSCP V1 L4)
I have been talking, via email, to Raymarine Sydney, but have not found a solution yet.

[Tom - Raymarine - Moderator]

Hello ajhaddow,

I believe you were speaking with Jon here in the middle of last week, but that he wasn't able to reply to you until Friday because we were all out at Sanctuary Cove boatshow which finished yesterday. Our apologies for the delay. I also see that we've got a 'Delayed delivery' warning on his email to you - can you confirm that you did receive Jon's Friday email?

It's great that you've logged NMEA2000 data showing the problem - I will take a look at this as well and come back to you.

Regards,
Tom

[Tom - Raymarine - Moderator]

Hello ajhaddow,

I've read Jon's reply, and looked at the NMEA2000 data you've recorded and sent in.

The relevant data that we see in the recordings includes:

• current heading (as measured by the pilot)
• locked heading (pilot course-to-steer)
• course-over-ground (from GPS)
• pilot mode (Standby/Auto etc.)
• Demanded Rudder (the target rudder angle the pilot is aiming for when powering the drive unit)
• Virtual Rudder (the pilot's estimate of where the rudder is, based on drive output, back-EMF from the motor and drive-output modulation)
  

Attached is an annotated plot of some of these values in over a period of around a minute from that log. It appears that the pilot is struggling to apply helm fast enough to correct the swing of the boat. This could be because there's a mechanical problem with the drive or its effect on the steering, or because the programmed hard-over time in the pilot doesn't match the real drive-unit hard-over time, so that the pilot's drive output is resulting in less rudder movement than the pilot thinks is the case. The Demanded Rudder looks reasonable, and I'd be confident that this isn't an electronic fault as these don't produce this sort of problem. It could be a mechanical fault.

Some questions, then:

1. If (when underway) you press Auto and then make rapid, large course-changes (e.g. +10, +10, +10, pause a second, -10, -10, -10 and repeat), does the drive consistently produce a strong, even steering movements? Do you ever see a situation where the rudder bar (virtual rudder) moves but the steering doesn't? How does the drive sound? What kind of drive is it?
2. If you make a sharp, large pilot course change to get the helm to drive towards its end-stops, does the indicated rudder angle relate closely to the real rudder position? If you use the pilot to drive the helm to an indicated hard over (rudder bar) then go to Standby, where has helm ended up? Really hard over, or more central?
3. Making a note of your current Hard-over Time calibration option, what happens if you increase this value? Try stepping up in 1-second increments: does this change the behaviour?
4. What Vessel Type is selected? It's worth trying the other types, since they relate to different models of vessel steering behaviour, even if the boat types don't look like your own.
   

Most steering performance problems are a result of an unusually slow or fast drive-unit hard-over time, or a hard-over time setup that doesn't match the drive's real value, and these problems can cause problems like what I see in your log.

Incidentally, re. your email - replacing the p70 will make no difference to this as it's purely a display/keyboard, it makes no course-keeping decisions. Similarly a *display* reset will have no effect, though a pilot (EV1) reset or Compass Restart would. After a compass restart, the EV1 will recalibrate as long as you're under way at >3 & <15 knots, and turning.

Regards,
Tom