Autopilot and rudder stops, URGENT

Moodyjim

Moodyjim

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This is a comment from a survey on my Moody 425 and I'm not quite sure what the surveyor means.

"The autopilot has been installed in such a way as to not allow the rudder to come to its rudder stops. This means that the actuator is acting as the rudder stop and that is not acceptable. Either the stops have to be extended or the installation redone."

If the A/P is engaged then surely this is correctly installed but if it isn't engaged then are actuators adjustable? I think it's the original installation although the A/P is a Raymarine replacement 5 years old.

Jim
 
Not seeing this may offer only: the rudder pilot is 'too short', so to say, cannot extend enough to put the rudder hard over (to it's stops). So should be connected on the tiller farther aft. May happen that in such position it will have too little leverage then, quite possible this tiller pilot is just too small for the boat. But then it works, doesn't it?
 
before installing my 6000, the rudder would turn 45 deg each way.
the max the 6000 can turn is from memory just over 20 deg.
i had strops made in 7 x 7 ss wire to limit the travel of the ram & quadrant.
this is what your surveyor is talking about
 
The rudder stops are set to maintain the rudder at the optimum operating angles. Apparently if the rudder operates beyond these angles turning efficiency is reduced and loads on the rudder shaft increase. If the boat is surfing then it may require stop to stop adjustment to keep her under control which you will not be able to do. Then there is the case where the ram takes load at its full stop position when its not steering. This tends to load up the piston rod and any fasteners which they are probably not designed for this i.e. the rudder is supposed to hit the stops before the ram extension bottoms out. Thats how I see it.
 
That would seem to be right. The suggestion to move the actuating arm nearer to the rudder pivot would seem a good suggestion. If it can't manage a bit more effort then it's going to be struggling anyway, I would have thought. Modifying the stops would limit the available travel as already suggested.

Surely the unit must have excess capacity unless an under-specified unit was installed in the first place.

Being cynical. If the boat is sold, just move the attachment point. Not your problem if 6 months down the line it gives up.
 
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Well I've spent 30 mins. holding on for Raymarine and still not through!
It's wheel steering on the 425 of course, sorry if that wasn't clear.
"Then there is the case where the ram takes load at its full stop position when its not steering. This tends to load up the piston rod and any fasteners which they are probably not designed for this i.e. the rudder is supposed to hit the stops before the ram extension bottoms out."
I think this must be the case but never having seen the installation I can't be sure. So it means moving the actuator nearer to the rudder tube so that it has more reach - is that correct? Probably not a huge job by the sound of it.
Jim
 
If you move the ram to the centre line the ram will have insufficient travel inwards toward the ram.
Leave the ram alone & move the rudder limiting stops
Moodyjim said:
Well I've spent 30 mins. holding on for Raymarine and still not through!
It's wheel steering on the 425 of course, sorry if that wasn't clear.
"Then there is the case where the ram takes load at its full stop position when its not steering. This tends to load up the piston rod and any fasteners which they are probably not designed for this i.e. the rudder is supposed to hit the stops before the ram extension bottoms out."
I think this must be the case but never having seen the installation I can't be sure. So it means moving the actuator nearer to the rudder tube so that it has more reach - is that correct? Probably not a huge job by the sound of it.
Jim
Click to expand...
 
I read this that the autopilot actuator is acting as the rudder stops, something that it is not normally designed to do. If you know the autopilot model I seem to remember that Raymarine have all the manuals on line so you could check the installation requirements that way.
 
Moodyjim said:
Well I've spent 30 mins. holding on for Raymarine and still not through!
It's wheel steering on the 425 of course, sorry if that wasn't clear.
"Then there is the case where the ram takes load at its full stop position when its not steering. This tends to load up the piston rod and any fasteners which they are probably not designed for this i.e. the rudder is supposed to hit the stops before the ram extension bottoms out."
I think this must be the case but never having seen the installation I can't be sure. So it means moving the actuator nearer to the rudder tube so that it has more reach - is that correct? Probably not a huge job by the sound of it.
Jim
Click to expand...

The installation is certainly wrong, and could wreck the drive unit so it must be changed. If you haven't seen it, perhaps you should ask your surveyor's advice on the best way of fixing it. It could be that the rudder stops are adjustable.
 
This is a bit confusing as I have a hydraulic system with a Raymarine S3g and ST6002, the manual says to configure so that the autopilot cannot turn the rudder as far as the stops. The loads involved are colossal using a ram and that repeatedly pushing against the stops and trying to push further will damage the stops.
 
Lazy Kipper said:
This is a bit confusing as I have a hydraulic system with a Raymarine S3g and ST6002, the manual says to configure so that the autopilot cannot turn the rudder as far as the stops. The loads involved are colossal using a ram and that repeatedly pushing against the stops and trying to push further will damage the stops.
Click to expand...

Don't think it is confusing. The OP's installation has been done in such a way that the rudder can't reach the stops, so the only thing taking the strain is the linear actuator, which isn't designed for this. Raymarine usually recommend programming the autopilot so that it can't push right against the rudder stops, in order to avoid putting the installation under excessive load.
 
pvb said:
Don't think it is confusing. The OP's installation has been done in such a way that the rudder can't reach the stops, so the only thing taking the strain is the linear actuator, which isn't designed for this. Raymarine usually recommend programming the autopilot so that it can't push right against the rudder stops, in order to avoid putting the installation under excessive load.
Click to expand...

OK makes sense
 
Moodyjim said:
This is a comment from a survey on my Moody 425 and I'm not quite sure what the surveyor means.

"The autopilot has been installed in such a way as to not allow the rudder to come to its rudder stops. This means that the actuator is acting as the rudder stop and that is not acceptable. Either the stops have to be extended or the installation redone."



If the A/P is engaged then surely this is correctly installed but if it isn't engaged then are actuators adjustable? I think it's the original installation although the A/P is a Raymarine replacement 5 years old.

Jim
Click to expand...

I doubt there is a single tillerpilot which has enough travel to reach the rudder stops and I'd be surprised if many quadrant mounted wheel-pilots could that either. One has to suspect the surveyor's professional competence.
Perhaps it would be an idea to find out what he does mean (unless of course he's doing a favour for the purchaser).
 
When I fitted my AP which is one under the decks you adjust the travel on the AP via the control head to limit the drive just short of the stops, this prevents the drive pushing against the stops and damaging either its self or the stops. However when steering manually the rudder can go to the stops ie it retains full travel.

If the ram is preventing the rudder from reaching the stops when the AP is disengaged, then something is wrong it may be its attachment to the quadrant is too far from the rudder shaft, or it's the wrong ram for the job as it has too little travel. Definitely wrong either way.

Cheapest solution would be to move the ram attachment position to the quadrant closer to the rudder shaft. Probably would not need to be moved far.
 
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"Linear drive
Make sure rudder movement is limited by the steering system end stops
before the push rod reaches its end stop. Failure to do this could damage
the drive and will invalidate the warranty."

http://www.raymarine.co.uk/manualse...pilots&Documents=&LanguageType=&Search=Search
Universal IO Drive Installation Instructions 81180-4.EN
Page 14

It's OK for the Ram to hit the quadrant stops, in fact it is required!
 
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