Auto Pilot Excessive Yawing

I've just been looking through a manual on the Raymarine website and I saw that about measuring the time from hard over to hard over, said you had to do it if there wasn't a rudder reference sensor and I'me not sure if we have one fitted, haven't seen one. I'll give that a try.

Thanks

There is a rudder bar at the top of the control head, if that works you have the sensor, if it doesn't, you don't.
 
Going back to basics. The OP does not say if this is a long term problem or one that had has arisen after a lengthy C-19 induced layup! If the later it could be as simple as dirty connections on a plug / socket. Having looked at the manual it appears the sensor is solid state and assuming he does not have the rudder position indicator it won't be dirty potentiometer or such like. Once he has cleared the locker and eliminated that. if the problem still exists I would be inclined to go through all the connections a give them a clean with contact cleaner, Not WD 40. As usual not easy to diagnose on line!
 
The solution I found on a 35ft boat which had similar problem was to change to type 1 linear drive on the quadrant. I agree with those above who say the wheel pilot is underpowered and too slow for a 40 ft boat.
Aside from any power issue, any autopilot which drives the wheel rather than the quadrant has to cope with the inevitable play in the system. If there is too much play their first movement merely takes up the play and the course computer is still trying to get the boat to turn so further input moves the rudder too much, then the autopilot reacts in the opposite direction. Over steering is assisted by the flywheel effect of the wheel(s). You could try adjusting the steering cables to minimise any play, then go through the commisioning proceedure. Given the cost of a linear drive system a bit of work to adjust everything correctly is called for.
 
Had the same problem this year with my boat . Thought it was the auto pilot and a faulty windvane. Transpired when id re rigged the boat I altered the Mast Rake and boat was all over the place. Just another option to consider.

Steveeasy
 
Thanks again guys. There is no slack in the steering, you can see the top of the rudder shaft and it moves instantly when you turn the wheel. Responds to the helm straight away so I don't think that's the issue. Boat is in Greece and got plenty of use last year with no long periods of lay up.

I've tried to add a video of the head unit. Paul Rainbow, is that the rudder bar on the top of the screen?

Had the same problem this year with my boat . Thought it was the auto pilot and a faulty windvane. Transpired when id re rigged the boat I altered the Mast Rake and boat was all over the place. Just another option to consider.

Steveeasy
Problem exists under engine on a flat sea with no sails up, so don't think the mast rake could be a problem.
 
Still not clear whether this behaviour is new and it has worked fine in the past or whether it has always been like this. Have you run through the commissioning routine yet? It is explained in detail in the manual, and takes about an hour. It does 2 things, first aligning the compass and then learning the basics of how your boat steers.
 
David, yes that is the rudder bar.

On the ST4000 range it showed at the bottom. And needed the rudder reference unit connected to the quadrant to monitor ... the angle of the rudder.

I'm obviously wrong in assuming one is fitted to more modern units but fascinated to find out how the rudder position is now monitored.
 
David, yes that is the rudder bar.

On the ST4000 range it showed at the bottom. And needed the rudder reference unit connected to the quadrant to monitor ... the angle of the rudder.

I'm obviously wrong in assuming one is fitted to more modern units but fascinated to find out how the rudder position is now monitored.

Without the rudder sensor, it isn't.
 
Still not clear whether this behaviour is new and it has worked fine in the past or whether it has always been like this. Have you run through the commissioning routine yet? It is explained in detail in the manual, and takes about an hour. It does 2 things, first aligning the compass and then learning the basics of how your boat steers.
I’ve only been sailing the boat for about a year. To my knowledge it’s always been like this. The boat is in Greece and I’m in the UK, don’t go back back out to the boat until mid August. Hopefully with the advice and pointers from all on here I should be able to get it working. ?
Thanks again for all suggestions and advice.
 
Without the rudder sensor, it isn't.
So you agree it's the rudder bar and then say the rudder position isn't monitored by the sensor.

Sooooo ... nope ... I'm lost.

Paul, I'm really not picking a fight with you, it's the last thing I'd do .... you're the electric Volvopaul of this forum and really helped me last year with a problem, including sending me diagrams.

The only reason that I mentioned the rudder sensor is we were in Granville one day ... mega spring tide, the cill dropped, and the rapid inflow of water hit my rudder and slammed the wheel over with a bang.

Didn't think anything of it until I engaged the autopilot and the boat went all over the place.

It turned out that the shock had spun the sensor to its full extent (instead of its central position) and this disrupted the message being sent to the head.

"Excessive yawing" accurately describes the result of the sensor not working as it should.
 
I have an EV-1 and ACU100 on my tiller steered 32ft Fulmar and it works brilliantly.
Mine is RUBBISH & dangerous. If the boat (31 ft Hanse) is in a quartering sea & a wave pushes it round 70 degrees- which it will do because the tiller ram is too slow- the autopilot disengages with a bleep. If I am down below & do not realise then the boat is set with tiller hard over & goes into a crash gybe. In those seas I have to use my Aeries . That steers a poor course but it does get me a sort of general pattern I can rely on.
To make matters worse I have just had to spend £675 on a new ram as the old one burned out ( I was not told that I could have had it serviced for £280 but will do later as a spare) It was 4 years old. Now on my 7Th autopilot in 17 years.
 
So you agree it's the rudder bar and then say the rudder position isn't monitored by the sensor.

Sooooo ... nope ... I'm lost.

Paul, I'm really not picking a fight with you, it's the last thing I'd do .... you're the electric Volvopaul of this forum and really helped me last year with a problem, including sending me diagrams.

The only reason that I mentioned the rudder sensor is we were in Granville one day ... mega spring tide, the cill dropped, and the rapid inflow of water hit my rudder and slammed the wheel over with a bang.

Didn't think anything of it until I engaged the autopilot and the boat went all over the place.

It turned out that the shock had spun the sensor to its full extent (instead of its central position) and this disrupted the message being sent to the head.

"Excessive yawing" accurately describes the result of the sensor not working as it should.

What i said was the rudder position is not monitored if there is no rudder sensor. The bar at the top is the same bar as the older displays had at the bottom, as you say, it shows the rudder position as "reported" but the sensor, but only if the sensor is fitted, obviously.

The sensor is optional with the ACU100 and if correctly configured it should work fine without it.
 
Talking to a Raymarine guy, he said the rudder position can be estimated from the back EMF at the hydraulic pump, in the absence of a position sensor. Maybe there's a similar thing with wheels, and it's driving the control head’s rudder bar. My rudder bar is certainly active but maybe I have a sensor without knowing it.

Wanted to know if software upgrade would help with the ‘excessing yawing’ that my system seems to suffer from (EV-1, ACU 100, hydraulic pump). Upgrading sounds like a bit of a mission with no MFD though.

Didn't come away with 100% confidence SW upgrade would help, but adding a position sensor worth a go apparently (assuming there’s not one already).
 
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