Simrad WP30 Autopilot Drinking on the Job

Jan 13, 2015
95
Hunter 34 Deep Bay, BC
The Simrad WP30 Autopilot on my Hunter 34 has recently decided to start wandering aimlessly. Sometimes it will be fine, then suddenly it will turn one way or the other by as much as 45°. Sometimes it will wander back and forth; sometimes it will simply decide it wants to keep on a new course of its own choosing. Sometimes it will gradually creep to one direction or the other (port most often) until it is quite far from the course I set it on. Prior to this it has always worked fine in the seven years I've had the boat.

Nothing has changed in the area magnetically, i.e. I haven't added a large chunk of metal in the vicinity. I'm trying to decide if it has simply died of old age, or if there is something I can do to recalibrate it. I singlehand often, so I need this thing working. If it can't be salvaged, then it's off to install a new system; probably a piston-style attached to the rudder post in the lazarette.

Does anyone have any ideas?
 
Jan 7, 2011
4,727
Oday 322 East Chicago, IN
On my Raymarine autopilot, I had to “swing the compass” once to fix the “Crazy Ivan” behavior. You might look up how to calibrate a Simrad and see if that helps.

Greg
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Sounds like your AP has lost it’s way.

Re calibrate or sometimes called “Commissioning”.

This will reset the flux gate compass. Your manual should have the procedure.
 
Jun 11, 2004
1,621
Oday 31 Redondo Beach
These units are getting pretty old.
Could need calibrating. Never hurt to do that when weirdness happens.
Have you adjusted the belt tension?
Have you ever replaced the belt?
Do you have the manual?
 
Jan 13, 2015
95
Hunter 34 Deep Bay, BC
I have the manual, but there is nothing that I can see about swinging the compass; the only options seem to be gain and sea state. I'll read it again more carefully, though.

There is also (this seems weird to me) no option to adjust the belt tension; in fact, opening it up to inspect/change the belt is not for the faint of heart. I did it once, and hope to never have to do it again. It requires about six hands and the dexterity of a gymnast to do it. Not so much to take it apart but to put it back together.

Given the age it's probably just time to bite the bullet and replace it. Thanks for all the comments.
 
Jan 25, 2011
2,391
S2 11.0A Anacortes, WA
I have the new RM wheel pilot. Had issues with it hunting all over the place. No setting seemed to help. Then one afternoon while anchored in the islands and after the third beer, I started playing with the wheel. Back and forth rather quickly. Whoa!! Seems there is some slop. Tightened up the cable on the quadrant and totally solved the problem..
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Page 23 of the manual identifies the Fluxgate compass calibration procedure.
The possible faults and solutions page mentions power issues and issues with the data signal as areas to check if the boat begins to wander off course. Page 22 of the manual last entry on the page.

I’d start with the compass calibration. Hope that helps.
 
Jun 11, 2004
1,621
Oday 31 Redondo Beach
I have the manual, but there is nothing that I can see about swinging the compass; the only options seem to be gain and sea state. I'll read it again more carefully, though.

There is also (this seems weird to me) no option to adjust the belt tension; in fact, opening it up to inspect/change the belt is not for the faint of heart. I did it once, and hope to never have to do it again. It requires about six hands and the dexterity of a gymnast to do it. Not so much to take it apart but to put it back together.
There is an adjustment screw under the arm you put up and down to engage the pilot. When the arm is in the up / disengaged position you can see the screw. You need a small bladed flat screwdriver.

If recalibration, as jssalem suggested, does not work and you have never changed the belt that would be the next thing to try. Yes it is a hassle but it is certainly doable (and easier and less expensive than a new autopilot). An extra hand is helpful but I have done it a few times alone.

Calibration and belt adjustment are both on page 25 (section 6.3 and 6.4)of the attached version of the WP30 manual.

Attached are a couple of pages from the service manual with some vague tips on how to fit the belt.

I've replaced the belt on my WP30 about 4 times over the years. The last time, the inner race was coming loose. I took it off cleaned it up and reglued it and it is working much better. It was previously having symptoms similar to yours.

Letr me know if I can answer any questions.
 

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Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
If the belt needs changing, I found the part number a long time ago (I have the WP32). Should be the same belt, I hope.

AT5-825-10 or 10AT5/825 (same part just different way of labeling)
 
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Jan 13, 2015
95
Hunter 34 Deep Bay, BC
Thanks for all the help, everyone. I think the belt tension is going to be the answer. During the last two days I noticed (1) that when the clutch was engaged with modest effort I can still turn the wheel [which didn't used to be possible] and (2) when engaged and on, I can sometimes hear the motor turning but the wheel doesn't. I was intending to try adjusting the tension today but the wind blew up well beyond what a poor little autopilot could handle, tensioned properly or not, so it'll have to wait. I probably won't leave the dock again this week. I put in a request to my local chandler to order a new belt and intend to replace that as well. The service manual section that Richard provided adds a few tips I didn't know about that should make it a little easier.

Again, as always, the help on this site is fantastic.
 
Jun 11, 2004
1,621
Oday 31 Redondo Beach
Remember the belt is not necessarily a chandlery item. As Brian said it is an AT5-825-10 belt (5mm per cog, 825mm long, 10mm wide). Essentially a "generic" item. You can find them online. The same belt for the 30 and the 32.
 
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Jan 13, 2015
95
Hunter 34 Deep Bay, BC
I know a lot more about this kind of belt than I did a few days ago...

You were correct, Richard, that it's not a chandlery item. It's not even a Simrad item; they don't sell them themselves. It's listed many places online, but not stock anywhere that I could find. I finally found a place that had raw stock in a warehouse somewhere in the U.S. that would cut two belts for me that will ship in about two weeks.
 
Jun 15, 2012
694
BAVARIA C57 Greenport, NY
I had almost the same issues with my Raymarine autopilot, except it would sometimes do a full 180. Sent control unit back for repair, which was going to be around $900.00. Bought entirely new system from Raymarine which works great.
 
Jan 13, 2015
95
Hunter 34 Deep Bay, BC
Just to close the loop - once I managed to get some replacement belts, I took it apart and found the belt was shot! The article about disassembly was very helpful, and I no longer fear pulling it apart and putting it back together.
1625885805536.png
 
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