ST60 Thruhull Speed & Depth Transducer Problem

[onlinelee]

Hi Friends,

before I call in the engineers I have a small problem I hoped you guys may be able to help with?

I clean and replace my paddlewheel for water speed every few weeks, normally without problem. With the power on and the transducer in my hands, a flick of the wheel registers speed on the helm display nicely. However, as soon as its inverted and thru the hull nada, regardless of what the SOG is. Everything else on the display at the helm seems correct.

With the blank in Ive been under the boat and whilst a little slimy there is no growth, I even gave the whole area around the exit a rub with an abrasive pad. Ive tried jiggling the transducer, taking it out and back in, all to no avail.

When I pull out the blank water ingress seems no different to how its been in the past,
I had considered poking a brush or something through the hull just to make sure nothing was in the tube, but surely the blank would do the same job?

Any ideas would be much appreciated.

 

[The Shadow Knows]

I originally had a paddle wheel but, eventually abandoned it in place. It used to crap up alot.
I use my chartplotter for SOG for exact readings.

After all, paddle wheels can be influenced by current direction if strong enough.
It's just not accurate.

 

[onlinelee]

Yes, fully get that, however, I prefer things that should work, work

 

[Sailor Sue]

What happens when you pull it out to spin by hand if you hold it in the proper orientation and spin? Could something be binding in the normal position?

 

[onlinelee]

Mmm, thats the only way I have not tried it, but I think inverting it to test ( to its correct in water orientation ) should only move the wheel away from any problem, assuming there was movement or obstruction but there really isn't any! However, I will try that too, thanks.

 

[capta]

After all, paddle wheels can be influenced by current direction if strong enough.
It's just not accurate.

Actually that is the only reason to have a speed log these days. It can show you if you have a current that the GPS won't necessarily show you.

 

[Kings Gambit]

I originally had a paddle wheel but, eventually abandoned it in place. It used to crap up alot.
I use my chartplotter for SOG for exact readings.

After all, paddle wheels can be influenced by current direction if strong enough.
It's just not accurate.

Forgive, but I question your appreciation of the role of the vessel's speed log (and how to use one), and therefore your advice on it.

 

[SEMPERAVANTI41]

I would also test spinning the paddle wheel slowly and see if you can get a steady reading of 1 or 2 knots. Perhaps when you "flick" the wheel it works, but a slow steady rotation does not.

 

[onlinelee]

I will try spinning the wheel slowly in the correct orientation, but when tested, the the speed displayed did vary from 0 - 18kts and then with the last flick went to 18kts and the dropped slowly to 0 as the wheel slowed to a stop

 

[JamesG161]

With modern Multifunction Display and Radar, the "Hull speed" activates many useful functions. However in Radar Tracking there is an "optional" SOG use.

I have to agree that eventually GPS tracking SOG will probably be the most convenient method.

I find my ST60 gives rapid MARPA radar tracking info, such as..
1) Collision Course warning
2) Passing distance, speed and ETA.
3) Course for collision avoidance

I do like my Wind Vectors of True and Apparent winds on the MFD.

It appears that My ST60 is faster than SOG.

__________

On the paddle wheel "lack of response" ....
The wheel must "Protrude" your hull precisely. Too much or too little = NO SPIN.

Plus it relies on a clean hull at least 10-15 paddle wheel diameters forward of the wheel to be correct. I would make sure more distance of clean hull, since I don't know your wheel position and your hull shape.

Jim...

PS: Fluid Dynamics stream lines is where I get the "fully developed flow" info for clean hulls.

 

[John T1594]

Here are some of the transponder troubleshooting strategies recommended by Raymarine: 1) Make sure the paddle-wheel spins freely and is not fouled. 2) The transducer may become infiltrated by water and should be pulled an allowed to dry out 24+ hours then tested by spinning the paddle-wheel. 3) The arms of the paddle-wheel may lose their magnetism and can be tested by seeing if they are attracted to an iron screwdriver. 4) Power down the instrument, Disconnect the GREEN and the bare SHIELD wires from the back of the display. Connect a multi-meter to the green and shield wires and set the multi-meter to continuity/resistance (ohms). Slowly rotate the paddle-wheel. As the wheel is rotated, the multi-meter should alternate between an open and closed circuit. One complete rotation of the wheel should open and close the circuit four times. If no open or closed circuits are detected upon rotation, the transducer has failed and should be replaced.

 

[onlinelee]

John, Ive seen that from Raymarine, thanks. However, mine works just fine, not in the water though!!
James, its been working for years, no problem, the male transponder fits into
a female aperture in a fixed position that can't change, its doesn't make sense!

 

[Rick D]

John, Ive seen that from Raymarine, thanks. However, mine works just fine, not in the water though!!
James, its been working for years, no problem, the male transponder fits into
a female aperture in a fixed position that can't change, its doesn't make sense!

I have the same issue I am troubleshooting. Mine is a 60+. I wonder if it is an issue with the flap? It is not an issue all the time; it is an occasional problem when I install the transducer. It also works like a champ when out....in any orientation and any speed.

 

[Kings Gambit]

This may not apply here, but I recently replaced my ST60 transducer which started giving spurious readings. On inspection I discovered that the internal wires between where the paddlewheel is housed and the block housing the wires leading to the panel had corroded through. I discovered this only b/c the two components separated as I was pulling the transducer out of the thru-hull. I figured it might have been operator error on my part b/c I sometimes soaked the paddle end in a diluted vinegar solution (i.e., acetic acid) to clear fouling.

 

[onlinelee]

Rick, when I pull out the blank it is lightly fouled so assumed there is no flap although have not taken that much notice. I think the only thing I can do is insert the transponder and dive under the boat to see what it looks like, after Ive tried the other suggestions. The key fact here is that it does work, just not when inverted and in the water, so I find it unlikely to be a wiring problem.

 

[Kings Gambit]

The key fact here is that it does work, just not when inverted and in the water, so I find it unlikely to be a wiring problem.

If it "worked" we wouldn't be having this discussion. Wires transmit the information that's not getting to the panel when the paddlewheel is deployed--so, you got me if it has nothing to do with wires/wiring. I suppose you've concluded that the cleaned wheel is not turning as the boat is speeding through the water.

Here's your solution. I spliced mine to the existing wires leading to the panel using 26 gauge heat-shrink butt connectors.

www.ebay.com/itm/Raymarine-ST60-Speed-Temp-Transducer-P120-ST800-E26031/371906715953?epid=1037176529&hash=item56975e2131:g:Ec0AAOxy14VRWtfF

 

[JamesG161]

James, its been working for years, no problem

I figured that.

Did you see if the O-Ring seal is properly seated/compressed and not "lifting" the wheel a bit on insertion?

Also , hull barnacles growth just forward of the well will block the spinning.

Just a silly reminder, the ARROW on top of the transducer must point perfectly forward too.

Lastly...
Can you Dive the boat and spin the wheel?
Jim...

PS: My ST60 depth meter has a internal transducer [sealed] wiring problem that has similar symptoms. Every time I hit a big wave on the bow, it goes from 10' to 80'

 

[onlinelee]

Kings, that's very kind of you, thanks. I totally get your point, it doesn't work However, in my humble view if you are right it wouldn't work at all or would have an intermitant fault, mine works all the time out of the water and none of the time in it. In my view that has none of the hall marks of an intermitant fault that corroded or loose wires would cause?

 

[Kings Gambit]

Kings, that's very kind of you, thanks. I totally get your point, it doesn't work However, in my humble view if you are right it wouldn't work at all or would have an intermitant fault, mine works all the time out of the water and none of the time in it. In my view that has none of the hall marks of an intermitant fault that corroded or loose wires would cause?

Get somebody down at the thru-hull to wriggle the wires while you are moving through the water and see if anythings lights up on your panel.

 

[onlinelee]

James, thanks, Ill check the o ring and grease it, the arrow does kind of give the game away And Im gonna dive it tomorrow and give feedback on my findings.