Raymarine Linear drive type 1 not disengaging after a hard night

[jpemb7]

Overnight sail and our newly installed linear drive worked perfectly in fresh weather. 20kn gusting 30kn
Put it on 'standby' to motor into anchorage and clutch would not disengage.
My wife wrestled with the steering until I was able to physically disconnect the drive from the quadrant.
This is a very dangerous failure.
Pulled the drive apart and found small score marks on the clutch faces where the clutch had slipped and stuck.
Used fine sand paper to smooth off the surfaces and now the drive and the clutch work fine.... for the moment.
Also found pressure marks on the rudder stops where the drive has been hard over.
The clutch will only slip when the load on the helm is too great for the drive, right?
I didn't think we drove the boat too hard during the night. But at the beginning we did have a round up before reducing sail.
It could have slipped & scored at that time and then stuck later.
This is a new installation.
I want to avoid this recurring. I would appreciate any advice or info re similar experiences.

[colemj]

If this is a new drive, I would send it back for replacement.

Mark

[jpemb7]

I intend to get it seen to but given we are in a remote location I want to keep it working until, you know, I can get somewhere to get it serviced.
So, I want to find out as much about this type of clutch failure as possible.
Grateful for any info, anyone has.

[Neptune's Gear]

In the AP setup there should be max rudder angles. Set it so it almost reaches the rudder stops, but not quite. In the manual there is normally a dockside setup and a sea trial setup. Should be in the dockside bit (at least it is for simrad/navico ones)

[TacomaSailor]

The same thing happened to us with an older Type 1 Linear Drive (Sept 2000)

Are you sure you hit STANDBY or did the following happen and you just thought you hit Standby?

I discovered that if the circuit breaker to the course computer is turned off, or if the course computer loses power for any reason, the linear drive will stay locked in whatever position it was in when the power went off. If the rudder is hard over then you'll be making circles till you figure it out.

11 PM - 30 miles west of California 35 knots gusting to almost 50 with 10' breaking seas. Sailing almost downwind with just a double reefed main.

By the time I resolved the problem we had done a 180 degree turn and were headed straight into those breaking seas.

I have accidently turned off the autopilot circuit breaker a couple other times and the same thing happens each time.

It seems like a poor design and I would expect that Raymarine has fixed it by now.

[colemj]

I just tested this with our Simrad AP driving a Raymarine type 2 linear drive. Both purchased and installed in 2012.

With the drive engaged, turning off the AP breaker immediately releases the clutch and drive.

Mark

[Capt.Don]

Originally Posted by colemj

I just tested this with our Simrad AP driving a Raymarine type 2 linear drive. Both purchased and installed in 2012.

With the drive engaged, turning off the AP breaker immediately releases the clutch and drive.

Mark

My clutch disengages too - I know because the master dc switch is at the base of the companionway and I've accidentally flipped the switch. Gives the helm watch person quiet a surprise!

[Capt.Don]

Also, Raymarine will repair this, essentially replacing all the parts for $650.

[Sailmonkey]

The clutch requires power to engage, so loss of power won't explain this. But if it hits the stops, as has already been said, set the rudder limits in software.


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[TacomaSailor]

Originally Posted by Capt.Don

Also, Raymarine will repair this, essentially replacing all the parts for $650.

In summer 2013 I replaced the motor in our Raymarine type 1 linear drive with a Type II motor. I also replaced the drive belt. That project cost me $375 and about two hours effort (most of which was dismounting and remounting the drive unit in a difficult to reach aft compartment).

I can't imagine the clutch would cost that much more but it is a marine part.

Working on the Linear Drive guts is pretty easy.

[goboatingnow]

The drive is being run so that the lead screw and ball are being pushed against their internal endstops, this damages the clutch and can lead to binding

repair it and ensure that the drive is never pushed against the endstops. The Ray arm should be installed such that it has at least about 10% additional travel then the worst case quadrant movement from physical end stop to end stop. This is also the case when not under AP control and the arm is connected. It must never be dragged against its internal end stops

[jpemb7]

Thanks for the replies.
Neptune's Gear: I have been through the 'setup' process " setting maximum rudder angles in the software. I'll do it again but turn the wheel just short of rudder stops and not hard over, as requested in setup.
TacomaSailor: In the frantic confusion of a accidental "roundup"..could I have missed the standby button ? whistling:
goboatingnow: I know the drive hits the rudder stops before it hits internal end stops. I have physically tested this. There is a serious dent in the rudder stops that wasn't there before which confirms this. I think this might be the likely culprit though.
I followed the head unit setup instructions. It requires turning the wheel lock to lock for maximum rudder angles. Doesn't the acu use this angle info to stop the drive just short of the rudder stops. But obviously it has tried to drive right through them.

But can someone explain why the need to be careful with rudder stops/ drive end stops when the acu has data re: maximum rudder angles ? Or am I missing something?

Once again, appreciate any thoughts.

[jpemb7]

Ahh, of course. Rudder stop/drive end stop becomes an issue when the drive is NOT engaged.
So it doesn't necessarily come into play when the drive is engaged, right?

[goboatingnow]

Originally Posted by jpemb7

Ahh, of course. Rudder stop/drive end stop becomes an issue when the drive is NOT engaged.
So it doesn't necessarily come into play when the drive is engaged, right?

There are several issues

(1) One is the drive must be setup so it never drives Into the ends stops ( either internally or externally )

When disengaged, the arm shouldn't be pulled into its internal stops. , this shouldn't happen if ( 1) above is followed.

If at any stage the arm drove into the rudder end stops, damage can occur.

Dave


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[jpemb7]

I think I know what happened.
My rudder is transom hung supported by pintles. The pintle bracket is bolted through the rudder. The bolts and nuts on the top bracket bear on the rudder stop when hard over.
The bolt thread protruded through the nut about half an inch on the starboard side meaning max rudder angle is more on one side than the other.
When I set the max rudder angle using setup the acu used the larger angle which made the starboard side vulnerable.
Hope this makes sense
I have cut the bolt just short of the locknut to equalise the angles and reset maximum rudder angle so it is well clear of the rudder stops.
Hopefully, I will have no more problems
Took the boat out today and all seems fine.
Thanks for your help.