Autopilot steering off course

[Sailshabby]

>>Welcome, good first question and well presented, which does its usual magic of getting fine and concise assistance.<<


Now that you've been welcomes and asked your first question properly, you're free to ask about cats v. monos, politics, guns on board, etc. going forward!

[MJH]

Originally Posted by V-Dog

1st post, please be gentle.

Currently moving a new to me boat down the Chesapeake; boat has Raymarine e95 MFD and p70 Pilot Controller. When I engage autopilot the boat turns to hard to starboard ~30 degrees from current heading but autopilot display still shows desired heading. When I press standby on autopilot the true course heading will then display. I deleted any GOTO waypoints and old routes. Only current work-around is tried and true hand steering.

Is there an easy button that I’m overlooking?

Thanks,
Andrew

There is a knuckle type joint on the Rudder Reference Unit connection. Check it to insure it is operating properly. Depending on your installation it might have disconnected giving you that 30 degrees starboard turn every time. Mine did and I had to drill/insert a very small cotter pin to fix it.

Good luck.

~ ~ _/) ~ ~ MJH

[svfinlandia]

Originally Posted by Nicholson58

+1 on the flux gate. I also wondered if the flag gate might be faulty.

Another +1 for the fluxgate compass. Someone stored a pipe wrench near mine once and the boat didn’t know which way to go!

Al, S\V Finlandia

[Paul Howard]

Could also be the Rudder Feedback Unit is either disconnected (accidentally) or faulty and the computer does not know where the rudder is.
Check the linkage to see if secure at the tiller arm on the rudder post.
the RFUs do wear out and there are flat spots with no reading. I had a unit do this and it would go hard over when it hit that spot.

[Scrimshaw4]

One culprit to check for is ferrous metal near the gyro compass. It can play havoc with course heading. Always good to locate it on a new boat to you. JMHO

[waterman46]

Originally Posted by edsailing

Raymarine APs will generally try to put you on the track line rather than the course to destination. If you have crosstrack error it will do a hard course alteration to get you 'back on track'.

This was true of all 3 different autopilots I have had, none of them Raymarine. It means that previously a waypoint was selected as the go-to and some function like "NAV" was selected to create a track from the original boat location to the waypoint. Perhaps such a track would be preserved as an active steering setting after a power-cycle reboot. I don't think so, and if OP always gets a turn in the same direction, unlikely.

[CassidyNZ]

In my experience, a magnetic influence near the fluxgate will provide random results. The OP appears to have an identical deviation each time the AP is set. I reckon it’s not an external magnetic influence.

As Scrimshaw says, “it can play havoc with course heading”.

YMMV.

[Jim Beck]

Do you have a Raymarine Evolution Autopilot system? If so, check the location of the EV-1 Sensor Core and determine if you have any interference.

We had a similar problem, except the amount and direction of the turn we experienced varied based on the direction we were traveling. If we were on a north -south axis, we would get a 20 degree turn when we engaged autopilot. If East -west p, virtually none. We relocated our EV-1 when w3 found it was too close to the rudder drive motor and have had no further problems.

[Bittern]

Hello. I echo Dsanduril's warning on ferrous metal. We searched for some time, finally finding some chain near our fluxgate. Doing nothing but moving the chain cured our problems 100%! Good luck. Peter

[SaltyMetals]

My RM AP had been working fine but then i found a 25-30 degree error so re-callibratated (you will find the procedure in the book which involves putting it into CAL mode and then doing 2-3 slow circles). But after doing that it would then drop back to misbehaving again. Solution was simple. A guest had plugged in their phone to re-charge and the location of the socket of the socket is just above the cupboard in the aft cabin. The fluxgate compass on my boat (Jeanneau 43ds) is attached directly underneath in the top of the cupboard. So before you delve into other ideas already posted you might like to check this out. I have now taped over this socket so it cannot be used.
Andrew

[Martkimwat]

If this has just started to occur, have you checked to see if you have put anything ferrous near the compass core, in addition have you possibly had a near lightning strike (not a direct hit) My EV autopilot which I installed in 2018 just started to behave very erratically recently and would not hold its heading, I kept correcting it and eventually the indicated heading on the P70 was 180º different from my actual heading. Spoke to Raymarine and was advised to do an update first which sorted out most of the problems but still had a few issues and still required me to re-calibrate the setup. Discovered I had had a near lightning strike so have sent the complete A/p system back to Raymarine for their fixed price repair/replacement after contacting my Insurance company. According to my local Raymarine rep. the first thing Raymarine will ask you is if you have done an update, since there have been a few issues with erratic behaviour of their autopilot systems recently. If you have a Raymarine chart plotter with built in wifi, you can even do it over the web. I used my iphone as a hot spot and the updates downloaded in 28 minutes and took a further 30 minutes to install.The only annoying thing with doing the updates is it seems to wipe nearly all your settings and a lot of your preferences on the i70 instruments

[seacottage]

Every now and then my Raymarine Autopilot stops working properly. Most of the times the pilot compass and boat compass are out of sync.

I have always been able the fix the problem by loosening all connections on the computer and retightening them and by removing and cleaning all fuses and reinstalling them.

In my case the problem therefore arises because of bad connection(s).

[foggysail]

My old Robertson auto pilot went whacky last year as I made my way thought Wood’s Hole into Vineyard Sound. I remember the experience clearly......frightening! My solution was to replace that old system with a new Simrad AP44 auto pilot along with a new GPS HS60 heading sensor. There comes a time to consider the risks old electronics pose

[CassidyNZ]

Of course the other element that will cause erratic behaviour of a fluxgate is its proximity to the engine.

When I bought my boat in San Diego and left for New Zealand, the AP wandered all over the place. I went back, got the Raymarine agent to have a look and he discovered the fluxgate mounted in the engine room. It was immediately moved to the aft cabin and the problem was solved, remains solved 15 years later.

Apparently the rotation of engine components when it is running continually reassigns the magnetic field around the engine and the fluxgate becomes infinitely variable in its accuracy. True? Not true? Don’t know but moving the fluxgate seems to have worked.

[dfelsent]

Originally Posted by svfinlandia

Another +1 for the fluxgate compass. Someone stored a pipe wrench near mine once and the boat didn’t know which way to go!



Al, S\V Finlandia

An umbrella in the hanging locker made mine crazy.