I am looking for best autopilot settings for a wheel mounted Raymarine ST4000 MK II + for my Cat30. It snakes around quite a bit under sail at anything over 4 knots. If Allen Schweitzer of Drambuie in Boston sees this post I would appreciate hearing what settings he used. Thanks for your help.
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More ST4000 Setting Questions?
Bob, This has got to be one of the hottest topics on this forum. There have been many answers to your same question. Try using the search engine. Go to Forum Arhcives under the main Forum tab on the left, and type in ST4000. I'm glad I bought an ST3000. Good luck.
Bob, This has got to be one of the hottest topics on this forum. There have been many answers to your same question. Try using the search engine. Go to Forum Arhcives under the main Forum tab on the left, and type in ST4000. I'm glad I bought an ST3000. Good luck.
autopilot
Bob; On my ST5000, an under-deck model, I leave the response selector in the number 1 position, (automatic sea-state compensation) all the time. This provides the best compromise between course stability and current consumption. I would think the ST4000 is very similar, only wheel mounted. Make sure there's no metal near the fluxgate compass that can confuse it, too.
Bob; On my ST5000, an under-deck model, I leave the response selector in the number 1 position, (automatic sea-state compensation) all the time. This provides the best compromise between course stability and current consumption. I would think the ST4000 is very similar, only wheel mounted. Make sure there's no metal near the fluxgate compass that can confuse it, too.
autopilot
I recently installed the same on my C-30. It appears that setting the response on 2 or 3 corrects the snaking you describe. Just be sure to make it a default setting. If you do it underway you will need to reset it every time you power down.
I recently installed the same on my C-30. It appears that setting the response on 2 or 3 corrects the snaking you describe. Just be sure to make it a default setting. If you do it underway you will need to reset it every time you power down.
My Settings
Bob, I've got to say that I'm very flattered to be asked for by name! Here are the settings I used for my boat: Rudder Gain: 2 Response: 1 Turn Limit: 40 AutoTrim: 2 AutoAdapt: North (Big help up north) Cruise Speed: 5 Rudder Damping: 1 One problem I had with my boat was that my steering cables had too much play in them resulting in VERY poor performance (on the order of +/- 45 degrees). Also make sure you have a Deviance value that's relatively low (mine's 7 degrees). If it's higher than 10, I'd try to relocate the compass until you got a lower value. Let me know how you do...allens@mathworks.com Good luck! Allen Schweitzer s/v Drambuie C-30 Hull# 632
Bob, I've got to say that I'm very flattered to be asked for by name! Here are the settings I used for my boat: Rudder Gain: 2 Response: 1 Turn Limit: 40 AutoTrim: 2 AutoAdapt: North (Big help up north) Cruise Speed: 5 Rudder Damping: 1 One problem I had with my boat was that my steering cables had too much play in them resulting in VERY poor performance (on the order of +/- 45 degrees). Also make sure you have a Deviance value that's relatively low (mine's 7 degrees). If it's higher than 10, I'd try to relocate the compass until you got a lower value. Let me know how you do...allens@mathworks.com Good luck! Allen Schweitzer s/v Drambuie C-30 Hull# 632
rudder gain
I just set my rudder gain from 5 to 3 on my C-30MkII, and that got rid of the snaking problem I was having. All the other settings everyone suggested make sense to me. I did not make it the default, which I will have to do. A good point made!
I just set my rudder gain from 5 to 3 on my C-30MkII, and that got rid of the snaking problem I was having. All the other settings everyone suggested make sense to me. I did not make it the default, which I will have to do. A good point made!
Autopilots
A rudder gain of "2" is generally adequate for most cruising boats of this class. Remember this is an electro-mechanical feedback control system & is sensitive to all the external forces acting upon the boat. Excessive input (forces) acting over too short a time (repetition period) can drive the system into an unstable condition (oscillation, or wandering). The rudder gain setting attempts to establish the optimum damping under most conditions -- setting it too low will result in long response times, setting it too agressive will result in "hunting" around the desired course line and even over compensation (can cause a jibe). My experience (Cat320 with ST-4000) suggests the system is fairly sensitive to sail trim. Too much weather helm with a low rudder gain setting will cause wandering, as will just the opposite with too agressive a setting. With a heavy lee helm, you're in trouble either way. Getting the helm/sails balanced before engaging the autopilot is a good practice (and it conserves much battery power). When helm/sails are well balanced, any rudder gain setting will work well (for a while). One final thought -- we tend to set the autopilot to track to a heading, but they can be used to track to a wind direction (if you have the interconnected wind instrument). Tracking to wind angle is generally easier on the system once you get that balance. This wind angle tracking mode is especially important if you are running downwind, as will tend to prevent jibes. However, the crew must be sensitive to wind changes relative to the direction they will take you. --Ron
A rudder gain of "2" is generally adequate for most cruising boats of this class. Remember this is an electro-mechanical feedback control system & is sensitive to all the external forces acting upon the boat. Excessive input (forces) acting over too short a time (repetition period) can drive the system into an unstable condition (oscillation, or wandering). The rudder gain setting attempts to establish the optimum damping under most conditions -- setting it too low will result in long response times, setting it too agressive will result in "hunting" around the desired course line and even over compensation (can cause a jibe). My experience (Cat320 with ST-4000) suggests the system is fairly sensitive to sail trim. Too much weather helm with a low rudder gain setting will cause wandering, as will just the opposite with too agressive a setting. With a heavy lee helm, you're in trouble either way. Getting the helm/sails balanced before engaging the autopilot is a good practice (and it conserves much battery power). When helm/sails are well balanced, any rudder gain setting will work well (for a while). One final thought -- we tend to set the autopilot to track to a heading, but they can be used to track to a wind direction (if you have the interconnected wind instrument). Tracking to wind angle is generally easier on the system once you get that balance. This wind angle tracking mode is especially important if you are running downwind, as will tend to prevent jibes. However, the crew must be sensitive to wind changes relative to the direction they will take you. --Ron
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