ST50 Wind

davel

davel

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The direction indication on this instrument has started pointing in random directions although the wind speed seems to be accurate. I suspect the head end (mast end) since the direction is reported consistently on a repeater I have fitted. The masthead pointer points correctly but the direction shown on the cockpit instrument is wrong.

I don't really know how the head unit detects and reports the direction. Can anyone offer an explanation of how this works or advise of any "debug" routines that I might follow?
 
If you have a deck level multi pin plug, I suggest you check this first since corrosion in the connections, or a poor contact can cause the instrument to misbehave. If you have no such connection then I fear you are right and the problem is at the mast head.
Morgan
 
I have the same bit of kit which seems to just want to point sixty degrees off the wind on one tack and 120 on the other, it doesn't matter where the wind is coming from. I've tried recalibrating many times but more or less just about to give up on it.
I guess though it is always worth going through all the connections just one more time to see if I have missed anything simple.
It was working fine last summer but threw the wobbler towards the end of the season.
 
I strongly suspect that you have a break or loose connection in one of the wires from the head to the unit. The break is somewhere between the head and the master unit (all the repeater does is repeat the readings that the master unit puts onto the Seatalk bus).

The places to look initially are:

1. Any connections at deck connector level or in a junction box where the cable comes into the saloon from the masthead.

2. The connection at the masthead. The whole wind speed and direction indicator unplugs and these connections can corode.

3. Any signs of chafe or breakage in the cable on its route from masthead to instrument.

4. ST60 and ST50 masthead windspeed and direction senders are interchangeable electronically. If you can borrow a known working one and take it up the mast you can show that it's the cable and not the sender unit. I am not sure if Raymarine changed the physical fitting of the masthead unit when they moved from ST50 to ST60 so make sure the plugs are compatible.
 
John,

I have the same ST50 wind problem. I've recalibrated the pointer on the head unit so that is correct but the remiining problem I have is that the wrong data is on the seatalk bus so the other instruments which use wind data are nonsense. I was about to give up and upgrade to st60 - premature do you think?

Also i read on here (after I posted of this problem last summer) that the st50 masthead unit is not interchangeable with an ST60 as the cups are larger on the ST60 unit and therefore rotate more quickly. I recall that the resultant wind speed error was about 30%. Some bright person suggested drilling holes in the cups to let wind through and then doing the maths to calculate the revised calibration given cups with holes in! That's way, way, way beyond my schoolboy physics (mostly forgotten!)

rob
 
Hi Robert,

Your post has made me do some research!

I have spoken to my contact at Raymarine and he has explained:

A couple of years ago the ST60 and ST50 wind head units were compatible inasmuch as the old ST50 wind head would read out correctly on the ST60 instrument display. This is the situation that we have on our boat.

A little before the ST60+ series came out, the masthead wind unit was changed and the calibration factor was altered on the ST60 wind instrument. This means that the latest masthead unit is NOT suitable for older ST series of instruments.

Howevere this doesn't seem to be your problem and I suspect you need to talk to Raymarine about your bad data transfer on the Seatalk Bus.

Hope this clarifies some things...

John
 
Had exectly the same problem last year with my ST50. After endlas hours of recalibrating and fault tracing, I gave in and called a highly recommended local expert. Within minutes of being on board he immediatly called it right and reckoned it would be the sender unit at the mast head. Up he went and confirmed that the sender unit was shot, through corrosion. I then discivered a couple of things. The 50 and 60 range are not interchangeable and that there are short supplies of the ST50 unit, which cost about £130 for the part fitting and the putting back on the masthead. You may now not even be able to get the parts, certainly Raymarine are making some great offers to get ST50 users to switch over to St60. The work was carried out by Mike Sparshot who operates out of Gosport and is a well known wizz on this stuff. If you need any firther details PM me. Good luck.
 
I had this same problem which I found a solution to last Autumn when I had the mast taken down to replace the rigging. When I unplugged the unit from the top of the mast,I found that the grub screw that tightens the arrow to the unit had come loose. I tightened this up and hey presto when the mast was put back I had a reliable wind instument again. Of course,this problem could also be caused by a number of other things,but it is well worth checking that grub screw.
 
Many thanks to everyone for taking the trouble to reply to my original posting and to offer good and useful advice.
I'll start with the connection check and then move on from there. If I discover anything that might be useful to others I'll report back.
 
Had the same problem last year, suddenly the wind indicator in the cockpit was showing about 30-50 deg of true on both tack. Tried recalibrating it by turning boat through 3 turns etc. Will try and check all connections.

This search functio is great. /forums/images/graemlins/wink.gif
 
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