Hunter 29.5 Autohelm ST4000 veers off course

[deangraham]

Hi there,

I ma just back from a few days out, on the way out the autohelm worked well but yesterday it started veering off to port or starboard by about +/- 10 or so for no apearant reason, any ideas?
Where is the autohelm compass fitted in the hunter 29.5.

I do have sony marine speakers in the cockpit, hopefully they are shielded.

thanks

 

[deangraham]

oh I meant to say there was no sea to speak of when this happened, following or otherwise.

 

[Sailm8]

Boy I hoe you find out. I have the exact same problem with the same boat. I have searched the forums and most common recommendation has been to add a rudder position sensor. Way too expensive for my taste.

 

[Steve Dion]

Do you have any radio speakers in the cockpit?

If you do have you tested having the radio turned off and determine if the problem still happens?

 

[Steve Dion]

Way too expensive for my taste.

$165 on e-bay!

 

[deangraham]

Yes, I'll try with the speakers off, good test.

 

[Dan Johnson]

St-4000

I found my old ST-4000 was sensitive to the metal framed seat cushion when placed near it's location. Moving the cushion to the other side of the boat away from it would return it to normal course-holding.

Are there any metalic objects near the control head? You may need to move it to a location away from the speakers and other metalic objects.

 

[deangraham]

yeah that was my first thought, unless the sensor / compass is not located in the control box. I did have the stereo running on the way out without affecting it either so I don't think its that but will still test that when this gale blows over.

 

[Runaway]

I had the same problem on my 29.5 with 4000 plus auto. Raymarine's fix was to add the rudder position sensor. Before spending the money I decided to be double certain my new to me boat was not already equipped with one. Upon removing the floor panel to get down the rudder post I discovered the problem. Loose steering cables! I properly tensioned them and my autopilot no longer appeared to be intoxicated. Not only did my autopilot hold a consistent heading within 5 degrees, backing the boat was no longer a crap shoot as to what direction we would head. Definitely worth a look before splurging for the sensor.

 

[deangraham]

Brilliant, thanks I'll definitely be checking that

 

[captainpat]

Everyone's suggestion is valid and needs to be checked out. The strange thing about your posting is that the autopilot was fine on the way out for your trip then acted up on the way back, when your course was reversed. This may indicate a compass problem. It may be necessary to swing ship in the calibration mode to re-align the fluxgate compass.

I had an issue with course wandering when using the ST4000 on a Legend 35.5, a common problem, especially with older Hunter's light weight, underwater configuration, short keels and spade rudders. The 29.5 is an excellent example of these characteristics. Changing the rudder response setting helped some but the problem never went away. UNTIL, ...a friend of mine changed boats and had a spare ST4000 drive unit that he gave me. I changed to that drive unit and the problem was all but gone. Turns out Raymarine made two different drive units; a black one (no longer made) and a gray one. The gray one is more powerful, has less moving parts, and does a much better job with course keeping. It is also more effective in stronger winds. You may want to purchase that drive unit if all else fails. There are some differences in measurements that you need to address upon installation.

I also found that whenever I talk to Raymarine Tech I always am advised to purchase something to correct a problem. They suggested, as with you, to purchase a rudder position indicator/sensor which, I am sure would probably help, but, to me, the newer drive unit is preferable. AND, it being still available you may be able to find it on ebay or some such place.