ST60 log not showing speed through water.

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santavey

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How do I test? I know the paddle wheel goes round ‘cos I tested on the hard.
SOG shows OK so instrument head OK.
Is it possible to detect a signal using a multimeter?
If so what would I look for and where would I look for it?

Found this from a previous post but not sure if relevant or what it would tell me.

Raymarine ST60 Speed Instrument Test

Press the outer 2 buttons for about 4 secs until beep heard
Press buttons 1 &2 simultaneously to start Seatalk check
When completed press buttons 1&2 again to do the LCD test
When completed press buttons 1&2 again to do the transducer test
Spin transducer within 10 secs of start of test

Not even sure if my ST’s are Seatalk


Thanks
JHT
 
If its been in the water a week or two it maybe the paddle wheel is clogged with weed or lobsters.
I normally take mine out, give it a good brush and spray with wd40, then replace.
Thats with the boat in the water..just make sure you have something to jam in the hole once you've pulled it ...
 
You need to clean the paddle wheel and spin it. you should see speed on the instrument when you blow the paddle wheel around...
A week is plenty of time for it to be jammed by marine life at this time of year.
 
But when you were testing it, did the instruments show anything? Which direction did you spin it? How long did you spin it for? Paddle logs (logs in general) have some damping to mute out false readings due to the effects of waves etc.

Just because it spins by hand doesn't mean there isn't enough friction to prevent water from rotating it.

I would agree with solway, take it out and give it a good clean (I keep a toothbrush under the floor panels for just that reason) and blast with W40.
 
Like MarkG says, the most likely culprit - and certainly the thing you should check first - is that the paddlewheel has been fouled by little critters. They love it in there. I'm not in your neck of the woods, but round where I am, fouling seems to be a bit worse this year than last (maybe it's the warmer weather?) and leaving the paddlewheel in for more than a week more-or-less guarantees it won't spin freely when under way.

Your transducer should have come with a blank plug that you can use to bung up the hole when you extract the transducer when afloat. Otherwise use a wooden plug. Depending on the exact model of transducer, there may be a flap inside the through-hull fitting that closes under the pressure of water once the transducer is withdrawn, but they're not terribly reliable - for some reason mine worked fine on hardstanding a couple of months ago but now resolutely refuses to close, hence admitting a small fountain of water each time I yank out the transducer. Have a bucket and sponge handy with which to mop up. You can also deposit into the bucket all the gunk and (surprisingly fast moving) little critters that you flush out from their hiding places in the paddlewheel and housing.

It's a little bit alarming the first time you do it, what with water entering and all, but you soon get used to it.

You can test the instrument while the paddlewheel is drawn. Get someone to look at the display while you flick the wheel round with your finger. Bear in mind that the wheel has to spin pretty fast to get a reading.
 
"You can test the instrument while the paddlewheel is drawn. Get someone to look at the display while you flick the wheel round with your finger. Bear in mind that the wheel has to spin pretty fast to get a reading"

Thats what I did....just wonder if they spun the wheel in the correct rotation.
Boats back in the water now so will have to withdraw the transducer. Noticed the blanking plug has a missing O ring. That should be fun!
I think either the wire is broken somewhere between the transducer and the instrument head or the transducer is kaput.
Or could I have lost the little magnet in the wheel the creates the pulse. Would that be obvious.
They do have little magnets dont they?
 
There is no right way to rotate it - although there is a front and back when it is mounted - yes they do have magnets - perhaps yours are missing ...
 
Mine didn't show a reading last Saturday when we set off. After about 5 minutes of gentle cruising through the harbour and it started working OK again. It happened once before last season as well.

I just put it down to a bit of weed or small wildlife.



Harpsden
 
Yes I am having to clear it frequently at the moment. Given that it works by the magnet you mention, you'll get the pulse, or series of pulses in either direction - a bit like AC.

Mine has been messing about a bit lately and having cleaned it properly, it still takes some time for the head to start computing. Maybe that is what is happening. Get it super clean and monitor it for 15 minutes or so.
 
_ _ _ is a 'no signal' sign on my ST60. It sounds as though you may have a connection problem from the transducer which worked when you were ashore, but which has now failed or is at least intermittent.

Even if the impeller was blocked, the display would still show '0.00'. BTW, my imellper stoped turning after just two weeks back in the water - something that hadn't happened in previous years. I withdrew it to find a MASS of little shrimp-like thingies in the housing! Flushed 'em out and all has been well since!
 
This is from the Raymarine website -

Testing the Speed Sensor:

•Verify that the transducer’s paddle wheel is free of marine growth and rotates freely on its shaft
•Power down the instrument
•Disconnect the GREEN and SHIELD transducer leads from the instrument display or instrument pod.
•Connect a multimeter to the GREEN and SHIELD transducer leads and configure the multimeter to measure continuity or resistance.
•Slowly rotate the transducer paddle wheel by hand. Note that as the paddlewheel is rotated, the multimeter should alternate between an open circuit and a closed circuit with each quarter turn. As such one complete revolution of the paddle wheel should open and close the circuit four times.

Should the multimeter respond as indicated above, then the speed sensor element of the transducer would be deemed functional. If not, then the transducer has failed and should be replaced.

It's worth checking the connections at the back of the instrument head - mine packed up and it was one of those.
 
Hi Solway, as I think has already been said --- means the problem isn't a jammed paddlewheel. Out of interest, what does your temperature display read?
 
Bringing an old post back up as my ST60 has also begun to play up. It started with under reading speed and therefore also log distance so in slack water I calibrated it to SOG using the seatalk link to my chartplotter. Temp is seriously under-reading at -4 and I can't adjust it up any more.

Firstly my speed worked fine until today when it reads 0.00 even with a positive SOG and temp remains at -4C.

Sugestions?

I will pull the transducer again and give it another clean, bi
but it went from reading fine to 0.00 in 4 days.

As for the temp, I haven't got a clue. I will try Raymarine on Monday.

The next step will be to open the instrument binnacle and check all the connections.

Any one else got any top tips?
 
Is your log showing a sensible reading for temperature? If not, the themocouple in the transducer is probably kaput. This causes the instrument to go into slave mode. It will show data from seatalk inputs, eg SOG, but not from the paddlewheel. If this has happened, a fix involves putting a resistor, about 10 kohm IIRC, across two of the terminals.
Edit Just read mcandersons post, thats the problem. Can't remember off hand which are the two t/c wires.
Further edit, brown and white wires.
 
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Temp is all over the shop.

Having a look at the Raymarine online help I thought the 10K ohm resistor was to check the temp function not a fix.

If it can fix the problems how would I go about fitting a resistor and where? The transducer looks completely sealed.
 
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