Re: Attention Autohelm ST7000 Gurus!


Brent Cameron
 

All autopilots work by utilizing a deviation from the current course over ground to the set course so it’s not surprising that it always does a (should be slight) turn to port as they need that deviation to be able to figure out the rate of change that they should be using to correct any deviation initially but it sounds to me like something isn’t right as it shouldn’t take that long to establish itself back on course.   Normally in waypoint mode, the AP gets confused if you have a significant cross track error but that is not the case here.  

Does it track well in heading mode?  If you set a heading, let’s say 180˚, will it track well to that heading?  When you tell it to turn say 10˚ to port, does it line up quickly on 170˚ and track that well?  You should see it go promptly to that heading without any overshooting.  If that’s working well then your sensitivity to deviations (RESPONSE) and rudder gain (how fast it actually moves the rudder) adjustments are ok.   With Response, you generally want to keep it as low as the sea state will allow (reduces battery drain) to react to a change in course.  I’ve not seen it need to be set over a 2 except in really heavy seas.  Same thing for Rudder Gain… if the pilot is responding sluggishly to big deviations, then you might have to wind up the gain a notch.  

You can check your AP compass by lining up on a known range and comparing your heading to the MAGNETIC bearing of your range (assuming you are on the line and pointed exactly down the range of course).  I wouldn’t get excited about a difference of a degree or two as your bow probably wasn’t pointed exactly at the range but if it’s out more than 4-5˚, you probably want to  make sure that your AP compass is recalibrated but before that, have a look to make sure nobody put something big and metallic (or electronic) near your gyrocompass as that could cause issues.


Calibrating your compass is easy to do in calm seas - you will be doing a BIG 360 turn so you need a bit of sea room for this.  You will also need to be able to steer in on a known bearing (like on a range) although in a pinch you can use your chart-potter’s GPS heading but that’s really a function of COG rather than boat heading.  Get the boat going about 2 knots in a straight line.  When ready, simply press and hold Standby for a second or so.  It should pop up “Adjust Compass”.   Now start a very slow turn taking 3 minutes to complete at least a full 360 degree rotation (so about 2˚/second).  When completed, your AP should show you how much deviation it corrected. (Anything less than about 15˚ is ok).  Now turn the boat onto your known bearing range making sure that the boat is not only on the bearing line but also that it is pointed directly down the line (I.e. not crabbing for current or the like) and then using the course change buttons adjust the displayed course until it agrees with your known bearing (remember to use the MAGNETIC bearing… not true when reading off the chart).  When you are happy with it, press standby for a second or so and you should be all set.    

The ST-6000/7000 series of AP are great pilots and easy to configure properly.  It sounds like it is working hard to get to a course but you shouldn’t see anything like 5-10 minutes to establish a course from these as they should lock in within 1-2 cycles on either side of set heading within about 30 seconds at absolute worst case.  

Brent

On Mar 29, 2021, 12:34 PM -0400, Ian Townsend <smlocalola@...>, wrote:

When I choose “Navigate” to a waypoint, the pilot steers the boat until it gets a 0.05 nm to 0.10 nm XTE to port every time. Then it course corrects by heading to starboard until it gets back on the rhumb line. Takes about 5-10 minutes depending on the wind speed. Anyone with the same experience? Would it have to do with compass deviation? I am using a Raymarine E Series chartplotter. Pilot is a rotary drive type.


Grazie tutti!

Ian
Loca Lola II
SM153


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Brent Cameron

Future Amel Owner & Amel Owner Registry Moderator

Oro-Medonte, Ontario, Canada

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