Raymarine Autohelm Failure

[Snowpetrel]

Just on the silicon grease thing, it has to be a non petrolium type of silicon grease. Anything petroleum based will apparently destroy the seals over time.

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[helenbates]

Morning / Evening. I will pass on all the questions / msgs and respond when I hear from them. Thanks!

[helenbates]

From the boat:

Units don't respond to +/- 10 when hooked up in standby mode. Unit is in dry compartment - no corrosion of any sort apparent.

We're opening up one failed motor today, then we're going to leave it. Tell guy who suggested factory reset and recalibration that is our plan B if 3rd unit fails - we don't want to mess with it now when working.

Thanks again

[chala]

Originally Posted by chala

take care of the autopilot and it should last well.

I have, as standby, an Autohelm ST 4000 control unit manufactured in August 1993, installed in the cockpit and so is the ram, which still works perfectly. Well build and properly installed these autopilot are reliable and there is no need for extra like grease or so called owners improvement.

Originally Posted by helenbates

Once off we found the power cables had basically sheared themselves off.

Not the best for the control unit, should not have happened if properly installed.

[DeepFrz]

It's looking more and more, to me at least, that the problem is in the plug/cable to the ram. I don't know where they applied the 12 volt power. If at the plug, are the pins locked in solidly or pushed back in the plug and not properly seated. Gently pushing on each pin will tell you whether or not they are seated and locked in place properly. I suppose it could also be one of the female pins as well and they can be checked if you have a small enough screwdriver to fit. Do the checks with no power to the drive unit.

For others interested there is a picture of the ram and tiller on the log. The ram is mounted in a dry location. Link was posted earlier in the thread.

[Snowpetrel]

Originally Posted by helenbates

From the boat:

Units don't respond to +/- 10 when hooked up in standby mode. Unit is in dry compartment - no corrosion of any sort apparent.

We're opening up one failed motor today, then we're going to leave it. Tell guy who suggested factory reset and recalibration that is our plan B if 3rd unit fails - we don't want to mess with it now when working.

Thanks again

Great that they are in a dry compartment, this significantly lessens the chance of unit destroying corrosion being an issue, and gives me some hope the non-functioning ram may be recoverable, rather than just a corroded mess of green slime...

The fact that the rams don't do plus 10 or minus 10 in standby is useful. Possibly to much resistance somewhere, either electrically or physically for the weak head unit to drive it. But when hooked direct to 12v it provides so much brute power that the unit has to move.

My thoughts on the cheif suspects are still the wiring between the head unit and the Ram. But it could also be a motor issue or gearing issue inside the ram.

The head unit could well also have a partial issue with its own power supply, possibly a voltage drop somewhere that is means the ram units are struggling anyway. Low voltage in the whole system drastically increases the startup loads of the ram motors, and a slightly worn motor or poor wiring might be enough to cause the ram not to work.

One possible reason for the ram moving out to its stop when in auto is that when it senses an overload (such as at end of travel) the unit may pump a short burst of power through in the opposite direction to move the ram away from whatever caused the overload. This may result in a cycle of the ram extending out one way before shutting down.

The plugs may have small screws inside them to hold the wires in. Might be worth inspecting and tightening them. My old unit has fairly small spade connectors on the back of the head unit. They were vulnerable to dampness and being bumped.

If the wiring cover has been damaged at any point moisture could have got in and turned that section of wiring into green or black mush, resulting in much higher resistances through the wire.

Maybe the head unit is in the bow and the ram is in the stern with 30 foot of wire between them. This alone will make for a big voltage drop that will stress the whole system, especially if the normal sized wiring is used, rather than upsised wire to deal with the longer run.

At least they have lots of time on the oars to think about it!

[helenbates]

So they finally figured out the problem!!!

We finally found the cause of all the rudder problems - the arm doesn't fit in the compartment so can only move the rudder a small bit in one direction - this causes the motor to be overworked and fail when pressure from wind/waves on that side. Good news is we can partially fix it, which should help protect third arm, and if first 2 motors failed a chance we can repair one. We'll be breaking into motor (s) tomorrow so we may need advice on hacking a repair depending on what we find.....

Watch this space I guess!

Thanks again for your continued support.

[chala]

Originally Posted by helenbates

need advice

First undo the cable gland at the actuator, “ram”, to prevent twisting the wires inside the ram, sometime hard to do.
Second unscrew only the portion that contains the motor. It is possible to do it by hand, strong hands, rowers should have that.
It is very difficult to un-jam a GP motor.
But before dismantling it is possible to manually test an actuator.
Extending or contracting the actuator (need strength) it is possible to hear and feel the motor spinning.
If the only way to extend and contract the actuator is by screwing or unscrewing the ram then it is likely that the gear is damaged, the satellite gear, very robust, can be exchanged if of the same specification. Some people have claimed to have repaired the ram ball race.
Re-assembly, make sure not to cross thread.

http://www.cruisersforum.com/forums/...0&d=1360679249

[Snowpetrel]

Originally Posted by helenbates

So they finally figured out the problem!!!

We finally found the cause of all the rudder problems - the arm doesn't fit in the compartment so can only move the rudder a small bit in one direction - this causes the motor to be overworked and fail when pressure from wind/waves on that side. Good news is we can partially fix it, which should help protect third arm, and if first 2 motors failed a chance we can repair one. We'll be breaking into motor (s) tomorrow so we may need advice on hacking a repair depending on what we find.....

Watch this space I guess!

Thanks again for your continued support.

Any news? Its nice to have an answer at least as far as what went wrong thanks, Hopefully at least one might be fixable, or at least the last good unit won't have the same issues. I guess this is a problem when you shoehorn all that gear and people onto a such small boat!

Cheers

[helenbates]

Hi Snowpetrel - I haven't had any updates on the rudder arm at all so my feel is no news is good news and we just hope that the precautions they put in place can safeguard that third arm and hopefully make it last another few weeks.

I think they have had to leave the other two unmended for the moment and just return to the primary focus of rowing.

But they are approaching 2/3 of the way now(hopefully this evening) so watch this space.

They were really appreciative of all your help! Thanks again

World Record Atlantic Crossing Attempt - Ocean Rowing Events

[helenbates]

HI everyone, I just wanted to quickly update you on the Atlantic rowing boys progress... they are fast approaching the 200nm to go marker and are into the last 10% of the crossing - if all goes to plan they will hit the South American coast on Mon 24th April on day 49 of their journey beating the world record by approx 1 day. Thus far that 3rd 'dicky' autohelm has held out. I wanted to thank you all for all your help and support. It was much appreciated!
World Record Atlantic Crossing Attempt - Ocean Rowing Events

[barnakiel]

When our Ray (model 1000) failed the result was the same: the arm extended fully and locked up. It was humidity on the PCB. The PCB wiped with alcohol and dried with a hairdryer the unit was fixed. It failed again, in the same manner, after about two weeks.

Moist air enters the case and salt crystals form on warm circuitry. These crystal short the brain. Ray never solved this.

b.

[joel383]

They got it!

[barnakiel]

Reading Webb Chiles blog from his most recent leg to Sta Lucia gives one some insight into Raymarine failure rate. I think he got very close to 9/10.

Only beaten by his Aurinco failure rate that was 9/9.

So they are definitely not the best design, build quality, or both.

b.

[Wotname]

First, a big congratulations to the rowers for their world record

Well done and you will be surely enjoying a break from the oars!

Originally Posted by chala

I have, as standby, an Autohelm ST 4000 control unit manufactured in August 1993, installed in the cockpit and so is the ram, which still works perfectly. Well build and properly installed these autopilot are reliable and there is no need for extra like grease or so called owners improvement.........

After owning 4 of these series of units, you experience is not matched by mine. The first was an original Auothelm brand and was very good. fast forward some decades to the "same" Raymarine units and the reliability went south. This appears to match that of other users but of course, we don't hear much about units that are working well. I must add that since new I have been using a small amount of silicon grease on the ram on my current 4 year old ST2000 unit, it has worked well (fingers crossed)

Originally Posted by barnakiel

When our Ray (model 1000) failed the result was the same: the arm extended fully and locked up. It was humidity on the PCB. The PCB wiped with alcohol and dried with a hairdryer the unit was fixed. It failed again, in the same manner, after about two weeks.

Moist air enters the case and salt crystals form on warm circuitry. These crystal short the brain. Ray never solved this.

b.

Where do you think the moisture laden air was entering the unit? I'm guessing the ram seals...

Regardless, if what you postulate is true, it should be an easy fix...

Waterproofing PCBs is a mature technology and there is no reason for this not to be done at manufacture - except of course, when accountants decide otherwise .

I have often seen PCBs dripping (sometimes running) with water in avionics boxes; units that go from -20C to +40C with 90+% humidity in a matter of minutes.

Originally Posted by barnakiel

Reading Webb Chiles blog from his most recent leg to Sta Lucia gives one some insight into Raymarine failure rate. I think he got very close to 9/10.

Only beaten by his Aurinco failure rate that was 9/9.

So they are definitely not the best design, build quality, or both.

b.

Maybe there is aftermarket business in providing a proper conformal coatings on the PCBs in these units