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ST4000+ Tiller Pilot "Crazy Ivan"

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CO923 View Drop Down
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Post Options Post Options   Quote CO923 Quote  Post ReplyReply Direct Link To This Post Topic: ST4000+ Tiller Pilot "Crazy Ivan"
    Posted: 19 Apr 2016 at 11:52pm
Our ST4000+ tiller pilot ram and control unit went back to Raymarine last Autumn after spending the summer turning hard a-port as soon as we engage auto. Apparently this is a common failure mode in the ST4000+ system - the one with 3 units - compass, control/display unit, and actuator ram - which many people on this forum seem to find perfectly OK. The manoeuvre is referred to as "Crazy Ivan" because it's like a manoeuvre some Russian submarine drivers liked to use during the Cold War.

It worked perfectly when I reinstalled it in December. On our first cruise of the new season, today, after four months ashore (of which more than 2 under a tarpaulin) it's gone straight back to "Crazy Ivan" behaviour. Furious is an understatement!

The compass heading looks fairly steady and correct when the unit is in Standby and isn't driving the ram. When I press the +10 degrees button in Standby, with the boat stationary and the ram not connected to the tiller, the displayed compass heading changes - this evening it dropped from about 25 deg to 0 in a few seconds. This only happens when I press +10, and NOT when I press -10. So it's not just about the power drawn from the battery or I'd expect to see the same problem both ways.

Lots of posts have lots of theories. Everyone obsesses with metal near the fluxgate compass, but I'm fairly sure that is not the issue. I think I am down to two options. Either 
1. There is voltage drop on the 12V line, which leads to noise, which affects the compass signal or the demanded compass angle - but if that's what is happening, why is the effect not random, why does the system always do the same thing? Or 
2. It's a fault inside the unit - most likely damp, which has been suggested, and consistent with the unit working when it got back from Raymarine but not now after it's been sitting in the cold for three months and in the rain as well for another month.

Sorry for the long ramble. 2 questions:
1. Anyone else had this or similar problems?
2. Has anyone else with an ST4000+ got their control unit out in the rain on the side wall of the cockpit? Or in the installations people are happy with, is the control/display unit better protected from the weather?

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Keny View Drop Down
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Post Options Post Options   Quote Keny Quote  Post ReplyReply Direct Link To This Post Posted: 20 Apr 2016 at 7:28pm
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Keny View Drop Down
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Post Options Post Options   Quote Keny Quote  Post ReplyReply Direct Link To This Post Posted: 20 Apr 2016 at 7:30pm
Sounds simple but have you checked the 12v on the unit whilst operating the ram? If it falls below 10v it will be out of spec.

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CO923 View Drop Down
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Post Options Post Options   Quote CO923 Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr 2016 at 8:14pm
Useful thought, thanks, Keny. Because of the way it's installed, getting at the terminals to measure the voltage requires efforts of a gynaecological nature, so not to be done lightly! However it doesn't seem to make much or any difference whether the engine is on or off, which is some kind of indication that the unit is getting enough volts.

There is a lot of chatter on the web about problems in ST4000s being down to water ingress. I managed to have quite a long talk with the guy who installed it many years ago, at Blue V Marine Electronics at Port Edgar. He said it was almost certainly damp - it's a common problem in East of Scotland weather apparently - and suggested taking the unit out, drying it out, packing it with silica gel, and refitting. This is about 6 hours work, given the gynaecological nature of the job mentioned above. However, the last two nice sunny days have made a difference! The system is definitely getting better, it takes much longer for the arm to wind right in than it did two days ago. I just got a 12 V hair dryer, so the plan is to get the unit nice and warm tomorrow to get it properly dried out, and then to put sikaflex round the edge of the controller to keep rain and seawater out. And cross fingers!

We had very heavy rain in January and early April. I should have been more careful sealing round it when I refitted it given the exposed position. 

I will report back in due course.


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CO923 View Drop Down
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Post Options Post Options   Quote CO923 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Apr 2016 at 7:29pm
12.4 Volts at the DC input to the control unit. My multimeter was misbehaving so didn't try it with the ram operating. I'll do that tomorrow.

Now drying the unit out in the warming drawer above our oven, trying to stop it getting too hot. I don't fancy stripping it down, that would be a last resort. I'll try it on the boat tomorrow, and if it works then, seal round the edges with Sikaflex to keep rain and seawater out. If not, as a last resort, strip down and put silica gel in.
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Post Options Post Options   Quote CO923 Quote  Post ReplyReply Direct Link To This Post Posted: 24 Apr 2016 at 11:47pm
This morning I took the back off the unit and sat it in the hot sun coming in through our living room window for a couple of hours. I decided not to put in silica gel because there isn't much room, and I reckon the issue was heavy rain getting through the seals rather than general humidity. I greased the seal, reassembled the unit, and with great trepidation tried it in the boat.

Success! The tiller pilot behaved perfectly for an extended period driving and sailing around in the Forth off Granton. I put a fillet of sikaflex all round the edges of the control unit where it fits to the side of the cockpit. That should prevent bulk rainwater or sea water getting to the seal of the electronics compartment, which after 15 years of service will not be as good as new. So here's hoping.

The moral of the story: Crazy Ivan behaviour with older Raymarine tiller pilots is likely to be due to moisture ingress in the control unit. To fix the problem, dry it out; to keep it fixed, keep water out! 

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Alastair D Pugh View Drop Down
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Post Options Post Options   Quote Alastair D Pugh Quote  Post ReplyReply Direct Link To This Post Posted: 26 Apr 2016 at 8:16pm
It's probably a bit late - spraying the board with conformal coating might help prevent reoccurrence.
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Post Options Post Options   Quote CO923 Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan 2017 at 4:47pm
Final final (I hope) update on this one. One of my co owners tested out the true meaning of the Contessa 32's reputation as "a submarine with sails" and as a result the problem recurred. Seems the water was getting in through leaks in the rubber press-switches on the front panel of the unit. 
 Brute force solution: fill the unit with desiccant, as advised by Alistair at BlueV, Port Edgar, and put the unit inside a Tesco ziplock bag before refitting. This worked all season. 
 This year's improvement will be a clear silicone or similar sheet held on with duct tape. 
 I considered the conformal coating solution but it's difficult to get the circuit board out without damaging the retaining clips, unless presumably you have the right tooling for the job.
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