ST 4000+ Auto pilot wanders 30 degrees

[trasel]

Does anyone know how to correct my wheel mounted ST 4000+ Auto pilot from wandering approx 30 degrees back and forth when I am motoring fast at cruising speed of 6.3 knots on my Endeavour 32?
At a slower speed of 4-5 knots it will wander a little less to about 20 degrees back and forth.
This is all during flat seas.

Is this something that can be corrected?

 

[Ralph Johnstone]

ST 4000+ Auto pilot wanders 30 degrees

wandering approx 30 degrees back and forth when I am motoring fast at cruising speed of 6.3 knots
Is this something that can be corrected?

The first question here is: has it always done this or is this since a recent set up ?

I'm presuming your setpoint (desired heading) shows constant while wandering.

Second question: is the wandering random i.e. anywhere at anytime or is it regular and periodic ?

If it is periodic, I'd suspect that the gain is set to high. Try reducing the gain to "1" in an extreme measure to see if it changes the performance.

No promises without being there.

 

[kloudie1]

Mine did that a lot until I put a rudder position sensor on it. The part where you set number of turns, lock-to-lock did not go low enough to accommodate my pedestal set-up. Once the sensor was installed, it straightened out extremely well.

 

[trasel]

Thank you for replies,
1-after setting autopilot on auto, going straight on a heading, it starts to overcorrect slowly than regularly 15 degrees back and forth than occasionally gets worse, all while compass heading on screen remains constant.
2- what is a "rudder position sensor"?

 

[kloudie1]

2- is a potentiometer that tells the autopilot computer where the rudder is positioned and how much it is being turned .. http://www.amazon.com/Raymarine-Rot...mr2&keywords=rudder+position+sensor+raymarine
Outrageously expensive but one can be made by using the correct center tapped rotary pot..
If your pilot does not respond to turning down the gain this would be the next step.
Note that the newest wheel pilots do not need one.. the older ones did if the wheel lock-to-lock is less than 3

 

[McIntoshUSA]

Kloudie1

I have the same problem. How does the rudder position sensor work. What is it mounted to? It looks like it's just a bracket.

Thanks

 

[trasel]

Thanks for info, guess I need to fool with the gain.
My wheel goes 1 3/4 revolutions - stop to stop.
The auto-pilot rarely wandered that much at slower 4 knot speeds but since recently learning that Ive been under revving engine, my motoring speeds have increased along with this 30 degree back and forth wandering.

 

[kloudie1]

Rudder Position

The position sensor connects to the steering post or sector and "tells" the computer where the rudder is and how much it turns when the wheel drive runs. Attached picture shows mine mounted upside down and connected to the sector.. That said, there was a lot of discussion a few years ago about the "Catalina Cocktail" which was a set of parameters used in the tuning of the 4000+ to make it work on Catalina 30's without the sensor.. Stu may have that at his fingertips.. if not search for Catalina Cocktail to get the settings to try. I tried about a bazillion settings and combinations and got it to where it was pretty good at motoring but really not good at sailing.. Now I am very pleased.. I talked a lot to the Raymarine tech folks and finally one told me that I probably needed a sensor.. The wires hook to the back of the computer .. The manual has some good info about the sensor. Good Luck with it!

EDIT .. on the top tabs on this site, click "boat info" then "downloads and general".. scroll down to "Raymarine 4000 manual"

 

[McIntoshUSA]

Thank you for the information and picture.

 

[kloudie1]

Welcome!

 

[Lee Hadjiosif]

Does anyone know how to correct my wheel mounted ST 4000+ Auto pilot from wandering approx 30 degrees back and forth when I am motoring fast at cruising speed of 6.3 knots on my Endeavour 32?
At a slower speed of 4-5 knots it will wander a little less to about 20 degrees back and forth.
This is all during flat seas.

Is this something that can be corrected?

If you decide that a Rudder position indicator/sensor is what you need, I have a brand new one for sale still in the box with all mounting hardware. I will sell it for half of the $270 they are asking on ebay. Let me know.
Lee

 

[sailaway78]

Mine would not

Mine would not even work that good without the rudder position sensor. Where do you have the sensitivity set. There are several settings that control how good a course it keeps.

 

[Jackdaw]

Any change something is interfering with your fluxgate compass??

 

[Terry in Naples]

I agree with the above, check to see if you have anything metallic around the compass. It really caused mine to act that way when i left a wrench lying beside mine.

 

[Ron Roman]

I had the same problem as you, until I installed the ruder position sensor.

 

[Bill Roosa]

You need to stet the "response" level higher. Check the manual under owner setup to discover how to change the "response level"
Do the cheap easy things first. a rudder position sensor is not REALLY needed but help the master control unit figure out the "rhythm" of the seas faster. That is it only takes about a minute to "get the feel and rhythm of the seas" verses without a rudder angle sensor it takes up to 15 minutes.
You could try letting it search for a while and see if it calms down after a while to confirm that it is a "response" issue or a rudder angel sensor issue.

 

[trasel]

Thank you all for your comments and advice...however I am still surprised that there isn't a commonly known remedy besides adding an expensive rudder sensor...I will check this week when I visit boat for any metal objects in the near vicinity of the fluxgate compass

 

[sailaway78]

Tech support

Raymarine has some pretty decent tech support. I would suggest you give them a call, and they can tell you if a rudder sensor is needed, and if not what to check for.

 

[DougM]

Before you start adjusting the gain sensitivity, which could be the culprit, go through the calibration process for the Fluxgate compass. The procedure is straight forward and is described step by step in the autopilot manual. It involves putting the autopilot in calibration mode, doing a series of slow circles under power until the compass sets itself. You can then adjust the deviation and it's good to go.

You should be able to get the gain adjusted to the point where the autopilot doesn't "hunt" at all in calm conditions. When sailing, if the sails are trimmed optimally, there shouldn't be much hunting going on either.

One thought, is there an outside chance that the rudder is loose on the rudder post and that it is moving a few degrees? Not too likely, but worth ruling out.

 

[trasel]

I agree with the above, check to see if you have anything metallic around the compass. It really caused mine to act that way when i left a wrench lying beside mine.

Ah hah!
Now that I think back, A friend was onboard just before last outing and was asking to see my large metal manual crank engine starting arm. I removed it from its normal stored location to show him and in a hurry to depart quickly for a brief flat seas motor outing, I think I LEFT THIS CRANK ARM ON THE CARPETED SOLE, RIGHT OVERTOP OF THE MOUNTED FLUXGATE COMPASS!
Thus probably affecting and deviating the autopilot compass.
I am not 100 percent sure that this is the cause of the wild swings back and forth with autopilot set...but it certainly makes sense.
Looks like there was a simple/ no cost solution to this problem afterall...gotta love this forum!
Thank you all very much for your well thought-out remedies, especially "Jackdaw" and "Terry in Naples", because you 2 , I think were right on...and I will confirm this solution on my next daysail which will be within the next 4 days and will give update.
I had originally thought the wandering autopilot problem was due to motoring at higher than normal boat speeds achieved on that particular day. :dance: