Auto Pilot Problem

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philfin

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I have a Raymarine auto pilot (ST600 I think) It has started to randomly turn its self off for no apparent reason, whether unders sail or engine. It can happen after 15 mins, 1 hr or 2. It works straight away again when reset. I first though that it was something to do with the engine charging system sending some strange fluctuations in current but as it happens unders sail also that idea is scuppered.

Any thoughts as to what could be the cause would be appreciated. Thanks
 
Does any other equipment glitch off at the same time (clue - you might hear a click on the VHF)? If so, then it could be a general power supply problem

Autopilots will trip out if they are mechanically overloaded. Does that seem possible or likely?

If you are on track mode (i.e. following a GPS track) and GPS lock is lost or the link between the GPS and autopilot (?SeaTalk) is lost, then again your autopilot can switch off, I think, not sure, check. In wind mode it does funny things when the wind instrument goes funny - it should, IMO, revert to a basic magnetic compass autopilot but my ST6000 doesn't seem to.
 
Check all of the supply wiring. I traced a similar problem to a dodgy cable connection. Autopilots draw quite a large current and if there is a high resistance somewhere in the supply the resulting reduction in voltage can cause the unit to trip to standby.
 
Hi Lemain,

Thanks for replying.

I haven't noticed any other instruments or electrical devices being affected, i.e. VHF but will listen out for it. I don't have it linked to my wind instrument yet, so thats ruled out. Also I only use it in the "point and shoot" type mode so whilst it is linked to my GPS, I don't use the track feature. Would losing a GPS fix affect the auto pilot still in that case?

I have the autopiot linked to its own fluxgate comass.

I guess though that at the end of the day it can only be either a fault in the connections somewhere or the unit its self is faulty?

For information it only started playing up whilst motoring to Lampedusa after about 14 hrs into the passage. It has been on the blink ever since then.

Thanks for your help
 
I saw a similar question posted on the Raymarine customer help website in the FAQ section and the suggestion was that it was simply lack of power. As has been said, the autopilot sucks out quite a lot of juice and it may be that while there is enough to keep the other stuff (VHF etc) going, while under sail, the power drain from the AP is just too much so the unit trips out. While this solution stands up under sail, it's harder to justifty while under power, but if there are fluctuations in charging rate that might be enough.
 
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Thanks for replying.

[/ QUOTE ]
You're welcome /forums/images/graemlins/smile.gif

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I don't use the track feature. Would losing a GPS fix affect the auto pilot still in that case?

[/ QUOTE ] No, and ditto the wind

[ QUOTE ]
For information it only started playing up whilst motoring to Lampedusa after about 14 hrs into the passage. It has been on the blink ever since then.

[/ QUOTE ] It might not be related but it is always worth thinking through what could have happened as a result of the passage. Is your steering free? I don't know that model of autopilot - can you check that it operates freely when not connected to the rudder? If the load on the electric motor exceeds a certain level (in most Raymarine models the current is monitored) then the unit switches out to prevent damage. This applies wherever the extra load is....someone playing with the helm while the pilot is on, helm lashed, stiff linkages, gearbox, rudder, rough seas, badly trimmed sails,...anything that causes extra load on the motor.

Was there ingress of water during that passage? Did you hit anything underwater? Could you have picked up a net round the rudder and it is still there?

A good old-fashioned electrical check is essential, of course, and I assume you've done the obvious? Check volts while under load - does voltage change much when the pilot motor starts to run? For the autopilot to drop out the terminal volts of the equipment would need to be quite a bit less than 12V (don't have the exact figure to hand) so if you have 12V+ at the terminals *at all times* then that isn't the problem.
 
I had this problem on a TP10. It was the plug used to connect in the cockpit. The wire to the unit had corroded and was losing intermitent contact. Cable cut and remade to the plug and problem solved.

If the unit is at full stretch trying to steer (auto tack) and is not positioned quite corectly the unit will come out of auto. unless you hear the beeps you will not notice untill you start to turn up or down wind. Mine also does this! But you get used to it and learn to live with it.... I know i must reposition the bracket... sometime
 
I had exactly the same problem with my ST6000. I beefed up the supply cable size, replaced the switch with an over speced switch, checked and double checked everything. I sailed across the Atlantic and it behaved totally randomly. It would go days without a hitch then turn off for no apparent reason. I eventually replaced the control unit and kept all the wiring as it was and I have never had a problem since. Incidently, I bought the complete replacement unit brand new in Budget Marine in St Martin for £1300. this was for the control head, the computer, the pump, the fluxgate compass and the rudder sensor. Try finding it for that price in the UK. Kept the old unit for spares.
 
Mmm

I hadn't considered that the course computer could be the bit playing up, will have a poke about at it.

No helm/rudder moves freely and pump isn't trying to push past the "stops". Sea was like glass the night it started (hence motoring) so zero strain anywhere. I really suspect power or wiring

I know they say that these units are "only and aid to navigation" and should not be relied on but its a bit much when you nip down to make a cup of tea and come back up to find yourself going round in circles! The only saving grace beingt hat I only do it when there is nobody about. Not just safer but a lot less embarrassing!

Thanks for all your ideas, I am armed now for another assault on the b...dy thing this weekend.
 
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I know they say that these units are "only and aid to navigation" and should not be relied on but its a bit much when you nip down to make a cup of tea and come back up to find yourself going round in circles!

[/ QUOTE ]That's totally unacceptable. Suppose it were to cause an unintended gybe or broach while you were at the chart table? You could lose the vessel in an extreme situation. These autopilots, installed and maintained properly, and used within their ratings, should never do that.
 
Yes your right, Having one that is playing up is probably worse than not having one at all. Accordingly I would never rely on my fickle friend in any dodgey circumstances.

In my experience with all things electronic though, the word "should" is very well used. We all know what they should do but..... quite often irregardless of insatllation, set up, maintenance etc they just "don't". I had a wind instrument that went crazy and speaking to the manufacturer, he told me mmm it "shouldn't" do that. To which I replied, I know what it shouldn't do, thats why I'm calling. Turned out to be a faulty unit. I could go on

Anyway, thanks again for your help...
 
I ended up heading off course several times when the auto pilot turned off. Went for several miles in the wrong direction according to the GPS! I ended up taping a small compass in the galley so I could spot if we were not going where we should
 
I agree with every word...and been there! Good luck /forums/images/graemlins/smile.gif
 
we had a raymarine st6002 installed recently and have come across the problem of the unit cutting out when the battery volts get too low. The low voltage can be hidden because it's the drive unit that draws the power and drops the volts. If the drive unit is not running when you measure them they appear OK. It will also cut out if the wheel is accidentially locked. We had a sheet tail that was stopping the wheel turning more than half a turn. Person on night watch reports that AP cut out but wheel could be turned freely. Next morning we discovered the offending tail.

While happy with the steering performance, we have a bug which is annoying. When we put in a waypoint and steer to it, the plotter (Navman5500) and AP lock up when we get to the waypoint. Need to turn both off to reset. Now we have to remember to cancel the "go to" when we get close to the waypoint. Anyone have any ideas on how to fix this bug???
 
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While happy with the steering performance, we have a bug which is annoying. When we put in a waypoint and steer to it, the plotter (Navman5500) and AP lock up when we get to the waypoint. Need to turn both off to reset. Now we have to remember to cancel the "go to" when we get close to the waypoint. Anyone have any ideas on how to fix this bug???

[/ QUOTE ] I have a Navman 5500i which I run variously from the internal GPS and the Raymarine head. I use the Navman as my primary feed into the autopilot and I have had the same problem very occasionally. I put it down to a conflict of individual data strings on the NMEA bus as we communicate from the Navman to the course computer on the NMEA bus and the course computer converts the data to SeaTalk for internal Raymarine usage. A bit of a dog's breakfast really, which is always the problem when a manufacturer charges off with a proprietary system, as Raymarine have done.
 
Does it switch off when in "standby" or only when in "auto" ??
A friend of mine had the same problem and it proved to be the ST6000 control head (instrument). But as his ST6000 was chained to other instruments we tried switching the seatalk connectors around to make the ST6000 first and last in chain to see if any other instruments were affected .......... as it turned out it was the ST6000 itself and would switch off also when in "standby" mode.

Alan.
 
the AP and the plotter don't switch off, they just lock up. The plotter shows the waypoint but won't respond to any input keys. The AP is in auto but shows the "no signal' message and stops responding to any input keys except standby. I need to switch off both at the switchboard to get them to work again. I don't imagine there's any way of resolving it short of buying a raymarine plotter. I can't use the navman AP as their drive unit is too long.

The steering performance is excellent. Left it steering in 35 knots up the tail and 3m seas. Only took over (as wind got to 50knots) because I was getting worried about the consequences of a broach.
 
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