trouble with Raymarine ST4000 autohelm

[HerbertFriedman]

Cannot get autohelm to hold course when under power at full throttle. Boat (87 E34) pulls to port and autohelm over corrects with 20 degree swings but on average maintains course. Do not know why it pulls to port, everything looked OK at last haul out, any ideas?

The autohelm is set at response level 1 (AutoSeastate) so "it ignores repetitive boat movements and only reacts to true variations in course". There is a level 2 which " provides the tightest course keeping possible" but at increased power consumption. Also, I think the rudder gain is factory set at midpoint so I could raise or lower this gain parameter.

At low engine speed, the autohelm is sufficiently stead to allow me to raise the mainsail and under sailing conditions, the autohelm seems to hold course without much course oscillation, the problem only occurs under full throttle conditions. Any ideas as to which autohelm setting to play with?

 

[Alan Gomes]

Cannot get autohelm to hold course when under power at full throttle. Boat (87 E34) pulls to port and autohelm over corrects with 20 degree swings but on average maintains course. Do not know why it pulls to port, everything looked OK at last haul out, any ideas?

The autohelm is set at response level 1 (AutoSeastate) so "it ignores repetitive boat movements and only reacts to true variations in course". There is a level 2 which " provides the tightest course keeping possible" but at increased power consumption. Also, I think the rudder gain is factory set at midpoint so I could raise or lower this gain parameter.

At low engine speed, the autohelm is sufficiently stead to allow me to raise the mainsail and under sailing conditions, the autohelm seems to hold course without much course oscillation, the problem only occurs under full throttle conditions. Any ideas as to which autohelm setting to play with?

It's been quite a few years since I had an ST4000+. However, I found that when I set the drive type to "hydraulic" it worked much better. And no, I did not have a hydraulic drive system in the boat, but I found the course keeping to be better anyway. In the ST4000+ manual (that I have saved on my hard drive, dated August 2001) this involves setting it to drive type 2. See the manual, p. 106.

Try that and see what happens.

 

[HerbertFriedman]

I will try that, thanks

 

[lindaloo]

Herb, just to clarify, does the boat pull to port at higher throttle settings when hand steered ? And if so, did this start recently ?

My 1987 E34 certainly does, you need to keep a firm hand on the helm when under power and over 4 knots. I use a bungy cord to counteract this and "neutralize" the helm to not overwork the autohelm drive motor. It has done this since I've had it.

As for the autohelm settings, I found the tightest seems to work best but it is busy. I haven't experimented with it in years. I like the auto-tack feature when the crew are otherwise occupied. It is a poor cockpit layout for single-handing so it really helps there.

Rob

 

[HerbertFriedman]

Rob, I need to do more test to determine the extent of the pulling to port effect, i.e. does this effect increase with boat speed? But at full throttle, about 5.5 kts in slack, calm water, the pull to port is strong. I have owned the boat for 3 years and I think it has been doing this all along but it has become a "problem" since I just started to use the autohelm, I just started to single hand.

When you say the autohelm overcorrection is helped by switching to the tightest setting, do you mean the response level 2 as opposed to the default response level of 1. The observation that this tight setting uses more power should not be a problem since at this time I would be under power, not sail.

I will try the bungi cord trick, thanks.

 

[Christian Williams]

Check "rudder gain".

Run "autopilot configuration" again.

I would, and have many times, open a thread at the Raymarine wheel pilot help forum. Keep trying, some of the techs are helpful and others not.

Other users may also comment there, and you can search for threads titles similar to your issue.

If it were me, I'd buy a new EV-100 unit for $1300 or so. The St4000 is at the end of its life and these marvelous and useful gizmos are essentially disposable.

 

[bolbmw]

I use 'unconventional' settings with my ST4000, which is basically setup as if I had a power boat with hydraulic steering, and with the response set to 2. Although noisy (it makes constant small corrections) it holds a course true.

 

[HerbertFriedman]

going with the level 2 response sounds like a solution for my excessive over correction under full throttle and since the engine is going full blast, I dont need to worry about higher battery power consumption. But under sail, is the higher power consumption draining the battery too much? According to the manual, changing the response level to 2 from 1 reverts back to the original setting when you shut down the system, unless you go into the "dealer" settings to make that change. So if I am going to motor a lot, it makes sense to change from response level 1 to 2. But the setting for hydraulic (power boat operation) from the sailboat operation seems like a more permanent change. Maybe I will try the response level change first.

 

[bolbmw]

If I recall correctly I also have rudder gain set to 2
so
Drive 2 (Hydraulic)
Rudder Gain 2
Response 2

I zero concerns with power consumption. Stereo and lights far outweigh the minor consumption of the pilot, and we do multi-day trips without charging.

 

[HerbertFriedman]

many thank, I will try those settings.