ST60+ Knotmeter Issue>>>Thoughts?

[Rick D]

My Raymarine ST60+ not-meter is making me nuts. The display would not read knots when I was moving after installing the transducer which I have been leaving out when not using the boat. I took out all the connectors and checked them; they looked good. Had my wife spin the paddle and it showed knots. Put it in for a trip. No knots. Checked all the connectors while underway. No change. Pulled transducer. Spun it. Showed knots. Checked to see if the transducer wire might be bad by rotating the transducer into various alignments. No dead spots. Inserted it for return trip. Looked at it 15 minutes into the trip (after freeing a halyard jam). No knots. My wife said it showed knots when we left our mooring and were motoring down the fairway. Nothing the balance of the trip. Checked other functions. Water temp, log, GPS speed all OK. When we returned to the slip, pulled transducer. Had my wife spin it. Good knots. Any ideas? I think that transducer has a flap in the housing which works to control inrush of water when the transducer is pulled. Wondering if that could be jamming it somehow? Doesn't explain partial working tho when we left the mooring. Any thoughts????

 

[Alec]

Could you possibly have some marine growth directly in front of the paddlewheel when it is inserted? It doesn't take much to stop it.

 

[Kings Gambit]

I recently replaced the paddle wheel of the transducer on mine. One of the paddles had broken. I don't see how that would keep the wheel from turning if only one were broken, but it might be something to check.

 

[Rick D]

Thanks, guys...

...good thinking but the bottom was just done and the paddles are all there. More ideas???
Yup, the arrow is straight ahead and the paddlewheel aligns with the arrow.
Rich, the orientaion is correct and the log function is the total, not the run which is, as you'd expect zero. And, I trouble shot both with and without cocktail

 

[arf145]

Are you sure that you are aligning it properly when inserting it?

 

[Rich Stidger]

My dear Rick, I am nuts, D.,

I have a ST50 but also have a similar flap to seal the hole to prevent heart failure and a two-foot drinking fountain. My transducer will only align forward and it also has a arrow marking for the alignment-challenged.

My assessment of your T/S is:

Since the display indicates a non-zero speed when you spin the wheel by hand, that eliminates a bad transducer and a bad display, and eliminates a bad connection except if it is intermittent.

When you look at the alignment mark, does it agree with the paddle wheel orientation? Mine is fixed but maybe yours is different.

You said the LOG function was good. Does that mean that the display indicated a fixed distance run or is that value incrementing? If the paddle wheel is not turning, then the LOG distance should not be changing.

Has one of your racing "buddies" glued a plastic cup over your transducer hole?

And finally, have you been drinking? If not, I think you should be.

Please let us know the final solution.

 

[Kings Gambit]

Seems like all you have are 1) paddle not turning in situ or 2) paddle turning but transducer not transmitting. I think you eliminated (2). So, replace the paddle wheel axle and wheel for good measure, and/or dive on the boat to see if the flap has dropped down to block the wheel from turning. Maybe the wheel hub has worn to the point where the wheel wobbles, periodically binding against the housing when deployed, etc.

 

[Ted]

ST60+ knotmeter issue

This does not sound like a problem with your instrument. Remove the paddle wheel by poking the axle out from one side of the transducer to the other with a paper clip or something slightly smaller in diameter than the axle. Make sure the axle is totally clean of any marine growth. Just the slightest amount will prevent the paddle wheel from spinning when placed in the water but will appear to spin freely by hand.

 

[Ron20324]

when the transducer is out, can you push a stick out the hole? I know- water ingress.

 

[Davidasailor26]

Can you try holding the paddle under a slowly running faucet while it is removed? This may give you an idea as to whether there is something binding that's hanging it up just enough to stop spinning when it's in the water. Spinning by hand may be overcoming the small amount of jamming friction that could stop the wheel from spinning underwater.

 

[JamesG161]

Seems like all you have are 1) paddle not turning in situ or 2) paddle turning but transducer not transmitting. I think you eliminated (2). So, replace the paddle wheel axle and wheel for good measure, and/or dive on the boat to see if the flap has dropped down to block the wheel from turning. Maybe the wheel hub has worn to the point where the wheel wobbles, periodically binding against the housing when deployed, etc.

Kings Gambit above quote the best shot at it.

But you might...

Have the admiral pull it and put in the seasonal plug/bung for the ST60 in place while you "calibrate it".

Try various spin test rates to verify similar rates, like Low Medium and High, matching the knot meter reading. It may show a high speed spin test but not slow speed.

Do the testing with the cable in the same approximate position and angle. It could be a cracked cable.

I clean mine with Lysol water and soft brush.

Partial working when underway suggests cabling more than fouling.

If yours has temperature, does Temp work?

You can download the ST60 Speed manual from Raymarine.

All of mine are SWAGS.
Jim...

 

[Rick D]

Good Thoughts All...

...what baffles me is that it works when out but not in (at least just for a short time recently). I will try a test at differing paddle RPM's to see how that goes. I'm sure the paddle wheel is totally clean. Ultimately, I think I may have to dive on it to see what's going on with the transducer in place. That's my current working theory, that somehow the flap is fouling it. I have never heard of such a problem tho, so it still seems remote. I just can't figure what else it can possibly be since I can't get any failure with the cable oriented differently. Jessh.

Suggestions still welcome!!

 

[Joe]

There's either an obstruction.... or ... the unit is backwards/sideways ... or... the wheel is backwards. I vote for obstruction.

 

[Southpaw]

Can you dive the bottom of the boat while the is transducer is in and spin the wheel and have the Admiral see if it works

 

[Chris Patterson]

Can you dive the bottom of the boat while the is transducer is in and spin the wheel and have the Admiral see if it works

That is all wrong. Have the admiral dive the boat, while YOU watch the meter..

 

[dugsmith98]

I had my transducer replaced, and the new transducer had to have a calibration from the instrument head. If you go into the set up for the ST 60+, in the manual, it will show you how to calibrate for the speed you are seeing on your GPS in a flat area.
Mine was showing 0.0 at 5 knots, so I increased the gain using this feature, and now it is spot on.
You are correct, it is not the paddle wheel, it just needs an adjustment for gain. (I think...)
Doug

 

[John T1594]

Speedo advice from Raymarine

I had a similar problem with my ST30 Raymarine speedo and contacted their customer service for advice. Here is what they recommended:

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.

The paddle wheel should have magnetic arms and can be checked.

Also, water may enter the transducer and damage the electronics. Raymarine says to let it dry out for 24+ hrs and recheck for function as above. “O” rings must be intact.

My transducer failed and I bought an exact replacement on the internet.

 

[JamesG161]

Ouch! I think the ST60+ needs GPS working to calibrate SOG. Check the calibration procedure and RESET your ST60+.

• 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.

Now you are talking...JohnT good idea.

Also one last thought....

Only half of the paddle wheel should be exposed to water moving(see diagram for thru hull in manual).

More than half exposed and it is not going to function right. Could your thru hull ferule be corroding?
Jim...

PS: Hoisting a schooner of beer to Chris who will soon be alone on his boat.:stirthepot:

That is all wrong. Have the admiral dive the boat, while YOU watch the meter..

 

[Rick D]

Excellent Advice!

Great info about both the calibration and the test. I will do both. I do think it is the wheel getting caught on something, but I will see that next time I'm at the boat and dive on it. The housing is plastic so there shouldn't be any corrosion issue, and anyway, the instruments are only about six years old. Weird issue!

 

[Ron20324]

I'm thinking something like marine growth is blocking that flapper from opening, and preventing the wheel from rotating.