st60 anenometer intermittent speed

drakes drum

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24 Dec 2014
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bristol & st mawes
My wind instrument has become intermittent but only the speed and it seems to depend on sea state. The bumpier the ride the worse the issue. But before I stsrt the tiresome job of checking the wiring for a break, could the issue be the mast head unit itself. It is 10 years old
 

FulmarJeddo

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20 Jul 2007
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Home-Sidcup, boat-Lower Halstow, Kent, England
Mine went intermittent before dying completely. It turned out to be broken wires caused by ware to the cables by the jib sheets where the cable exited the mast. It wasn't obvious as the previous owner had pushed the damaged cable back in to the mast. If it is damage to the cable, it is worth remembering that the screen is used as a return.
 

pvb

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It's almost certainly a wiring fault. Before you go up the mast, have you double-checked all the other connections?
 

SimonD

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27 Nov 2001
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Dorset
Mine has been driving me nuts. In the first season it started intermittently showing clearly wrong high wind speeds. I have eventually discovered that the connector at the top of the mast is (a) poor quality and (b) not waterproof. Go figure! I've dried and cleaned it several times and it's better, but not perfect. Does anyone know how to improve the reliability of this connector?
 

yotter

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3 Aug 2007
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Me Inverkip, boat Kip in winter, Craobh in summer
I had a similar fault a few weeks ago. The anemometer would be spinning but the readout on the ST60 was 0.0. I checked the wiring at the base of the mast and one of the wires was loose, not obvious until gently pulling on the wires. I was very pleased with the quick easy fix. Worth a check before going climbing.
Angus
 

ChrisRayner

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22 May 2013
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Surrey
The bearings on the vane and anemometer wear out eventually. There's a company in Dorset who will replace them. However the fault is obvious, as the cups are stuck, and the vane doesn't move. If it all appears to be in order from the deck then a careful search for circuit breaks comes before a trip up the mast.
 

drakes drum

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It's almost certainly a wiring fault. Before you go up the mast, have you double-checked all the other connections?

Yes. Now checked under the headlining where ther is a socket to allow mast down, behind the instrument panel and at the masthead. Alles in ordnung! All greased with silicone grease. None of the wiring looks frayed.
Wonder if the cups are rotating on the spindle? As I understand it, the masthead unit is a simple magnet past a sensor set up so nothing to go wrong
 
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Nigelb

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10 Nov 2012
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Winchester
I have similar issue, assuming it is not a simple wiring fault and you are going up the mast, have you seen that there is a small diagnostic PCB test unit available in the web for c.£49. Looks like it plugs into the masthead unit. Also you can obtain most of the component parts for the masthead sensor including the PCB as spares.
 

MikeCC

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Exmouth, Devon
There's a simple electrical test - details on Raymarine help pages somewhere that will allow you to check correct voltage/resistance for speed and direction. No need to spend fifty quid - multimeter will do it.

But first get some contact cleaner/IPA (not beer) and work the plugs/connectors a few times after application to shift the grime. Then apply contact grease.
 

pvb

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There's a simple electrical test - details on Raymarine help pages somewhere that will allow you to check correct voltage/resistance for speed and direction. No need to spend fifty quid - multimeter will do it.

But it works correctly, so no need to test. It's just intermittent, which the tests won't help with.
 

Mistroma

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Greece briefly then Scotland for rest of summer
There's a simple electrical test - details on Raymarine help pages somewhere that will allow you to check correct voltage/resistance for speed and direction. No need to spend fifty quid - multimeter will do it.

But first get some contact cleaner/IPA (not beer) and work the plugs/connectors a few times after application to shift the grime. Then apply contact grease.

I didn't find the test procedure very useful as fault wasn't always there and I seem to remember that it speed is derived from a freq. change, not just a voltage. Pretty certain that Nigel Mercier wrote something about testing this system. It did show that direction indicator was OK and that speed was doing something.

I found slight greenish deposit on masthead connector. A clean up with tissue, contact cleaner and then Contralube 770 solved the problem. I now remove the unit every winter apply a little Contralube and seal the open end with self-amalgamating tape. It is refitted in Spring with another smear of Contralube (overkill but has never missed a beat since first cleanup).
 
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