Why does everything have to break???

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Homer J

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What is it about boats that everything breaks

This week my ST60 autopilot is misbehaving

symptoms are
1) will hold a straight course in calm water
2) a bit of a gust and veers upto 90 degrees
3) following this autpilot heading misaligned with compass

im thinking that the autohelm has in some way lost it’s ‘grip’ on the rudder - is this possible? Any thoughts?
 
I checked that but there is nothing I can see.

So I am back to my original conclusion but I don’t know how the ram is connected to the rudder b
 
I’ve done several recals but they don’t last for long as the next wave disrupts it. I can only think that the drive arm is not gripping the rudder stock sufficiently anymore. I am wondering if someone on the helm forced the wheel whilst the autohelm was engaged last time we were out - does this sound plausible?

does anyone know how the ST60 connects on a Jeanneau 37?
 
To answer the headline question - it's called impermanence.

Apologies if it's too early in the morning for philosophy.
 
We had the same boat and autopilot, take the lid off the pedestal/instrument panel and check the wiring is dry, clean, a little electrical contact spray/cleaner might help.
 
You said the autopilot’s heading display ends up disagreeing with the compass. That’s clearly a sensor issue and not anything to do with the ram slipping on the rudder stock. Although if you have no idea how the drive unit is arranged on your boat then, as a separate issue, you should really go and educate yourself by taking a look.

Pete
 
prv said:
You said the autopilot’s heading display ends up disagreeing with the compass. That’s clearly a sensor issue and not anything to do with the ram slipping on the rudder stock. Although if you have no idea how the drive unit is arranged on your boat then, as a separate issue, you should really go and educate yourself by taking a look.

Pete
Click to expand...
I fully intend to when I get back to the boat but it’s just happened and I didn’t get time to look. It Could be a sensor issue if the ram sensor is loose on the shaft but I’m not sure it’s a compass failure as it works fine until a big wave hits.
I will update when I get a chance but quite interested to hear if anyone has experienced anything similar.
 
Homer J said:
I fully intend to when I get back to the boat but it’s just happened and I didn’t get time to look.
Click to expand...

I was just surprised that you've never even glanced at your own rudder stock, quadrant, etc.

Homer J said:
It Could be a sensor issue if the ram sensor is loose on the shaft but I’m not sure it’s a compass failure as it works fine until a big wave hits.
Click to expand...

There isn't a "ram sensor". There is a rudder position sensor, which is completely separate. But you described the problem as "autpilot heading misaligned with compass", which I take to mean that the heading displayed by the autopilot system (ie, what it's reading from its electronic compass) is different to what you see on the traditional compass in front of you. If you meant something else, please explain the problem more clearly. If I've interpreted your five words of symptoms correctly then it's clearly nothing to do with the drive side of the system and all about the compass sensor input.

The compass that went with ST60-era systems (as Paul says, ST60 isn't actually an autopilot, that's just the generation of instrument display head you have) does have mechanical gimbals inside (you can hear it rattle as you turn it over) so my guess with the "big wave" stuff is that something has come adrift in there. But again, this is predicated on your problem being the one you actually stated.

While we're extracting information, does the rudder position indicator on the autopilot head match the wheel position (or any other indication you may have of where the rudder's actually pointing)?

Homer J said:
quite interested to hear if anyone has experienced anything similar.
Click to expand...

I have experienced the problem you think you have (autopilot tiller slipping on the rudder stock) but that doesn't match the symptoms you described. I've also experienced the compass suffering a sudden large deviation (someone stowing steel beer cans near it, as Starfire describes) but you say you've checked that.

Pete
 
Homer J said:
What is it about boats that everything breaks

This week my ST60 autopilot is misbehaving

symptoms are
1) will hold a straight course in calm water
2) a bit of a gust and veers upto 90 degrees
3) following this autpilot heading misaligned with compass

im thinking that the autohelm has in some way lost it’s ‘grip’ on the rudder - is this possible? Any thoughts?
Click to expand...
From the symptoms and answers given my course of action would be:
1) Check if the Ram is still properly attached to the rudder quadrant. Most likelyit is, but it is an easy cost free check.
2) Carefully check and re-make all electrical connections in the system.
3) Look on ebay to buy a new Raymarine Fluxgate compass. There is a "new" one on sale now for £150, or a ST4000 control head and compass for £200. You could buy the set and try the compass, if it works then re-sell the control head.
If none of that works then it must be the "computer unit" and you could either buy another one of those on ebay or start again with the latest system.
 
Rafiki said:
From the symptoms and answers given my course of action would be:
1) Check if the Ram is still properly attached to the rudder quadrant. Most likelyit is, but it is an easy cost free check.
2) Carefully check and re-make all electrical connections in the system.
3) Look on ebay to buy a new Raymarine Fluxgate compass. There is a "new" one on sale now for £150, or a ST4000 control head and compass for £200. You could buy the set and try the compass, if it works then re-sell the control head.
If none of that works then it must be the "computer unit" and you could either buy another one of those on ebay or start again with the latest system.
Click to expand...

Good advice if he wants to spend a whole load of time and about a £1000 on used parts, when it might be a simple, no cost fix.
 
It is not the drive unit, the rudder feedback unit, the tiller arm, the rudder or anything else associated with those components.

If the heading is incorrect, it is:
  • Something to do with the heading sensor. Could be the wiring to it (highly unlikely), something interfering with it or the sensor itself.
  • The giro compass, if it has one.
  • The ACU has got it's knickers in a twist and needs a factory reset and a recommission.

Knowing the type of autopilot is essential.
 
Aeolus said:
To answer the headline question - it's called impermanence.

Apologies if it's too early in the morning for philosophy.
Click to expand...
No apology needed but may I suggest Entropy would be more accurate? The second law of Thermodynamics can be simplified to "everything goes tits up eventually" so don't be surprised if things go wrong, just be thankful it ain't happened yet!
 
Does an ST60 shaped control head actually drive a ram? I had one and I did not think it did. Usually it only powers a tiller pilot or a wheelpilot with bursts of plus or minus 12 volts to go one way or the other. Not enough power to drive a quadrant ram.

Mine got binned last year because of intermittent serious disagreement between the actual course and the course the system thought was the case, at which point it put the wheelpilot hard over onto the wrong course - that it thought was correct. Once on that new (wrong) course it steered again. I changed the compass unit (rattly black box) and thought it was fixed. Then it happened again, at which point I junked the ST60 type head and fitted a new system with separate computer and colour display - can't remember the model but it was about £1,000+
 
jwilson said:
Does an ST60 shaped control head actually drive a ram? I had one and I did not think it did. Usually it only powers a tiller pilot or a wheelpilot with bursts of plus or minus 12 volts to go one way or the other. Not enough power to drive a quadrant ram.

Mine got binned last year because of intermittent serious disagreement between the actual course and the course the system thought was the case, at which point it put the wheelpilot hard over onto the wrong course - that it thought was correct. Once on that new (wrong) course it steered again. I changed the compass unit (rattly black box) and thought it was fixed. Then it happened again, at which point I junked the ST60 type head and fitted a new system with separate computer and colour display - can't remember the model but it was about £1,000+
Click to expand...
I don't think you understand the cabling "the ST60type head" as you refer to it tells the computer what you want to do, the actual power to the ram is seperate cabling from the batteries via the computer to the ram
 
jwilson said:
Does an ST60 shaped control head actually drive a ram? I had one and I did not think it did. Usually it only powers a tiller pilot or a wheelpilot with bursts of plus or minus 12 volts to go one way or the other. Not enough power to drive a quadrant ram.

Mine got binned last year because of intermittent serious disagreement between the actual course and the course the system thought was the case, at which point it put the wheelpilot hard over onto the wrong course - that it thought was correct. Once on that new (wrong) course it steered again. I changed the compass unit (rattly black box) and thought it was fixed. Then it happened again, at which point I junked the ST60 type head and fitted a new system with separate computer and colour display - can't remember the model but it was about £1,000+
Click to expand...

John, think of the ST60 controller as a remote control. It was fitted to many early Raymarine autopilots systems, which would have had several possible ACUs (computers) and several drive solutions. It could have been connected to wheel or tiller pilot, as you mention. It could also have been connected to a "black box" ACU (of several versions), which in turn would control the below deck drive unit, which, again, could be of several types.

This is why i keep saying we need to know what the actual ACU is.
 
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