Transducer paddle wheel

agriman

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Member
Joined
Feb 28, 2005
RO Number
16444
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57
My ST50 Tridata Raymarine unit stopped reading speed and log on the weekend. I'm thinking the paddle wheel fouled up. Can the wheel in the transducer be cleared or replaced without pulling the boat out of the water?
 
Instead of pulling the boat from the water, you could go in... :D
 
Depends on the transducer. Mine can be pulled out from inside the hull. Airmar B744 I believe. A flap partially blocks the opening so you don't sink.

On the other hand I don't ever do that. The insert has o-rings and they can get nicked when inserting, and then it leaks. And you better have more o-rings on hand.
 
Try just going under with a mask to check if the wheel will spin smoothly. It may just have a barnacle to be cleared off with a screwdriver. You may even have some luck underwater using a can of Teflon spray with nozzle straw directed at the axle at the sides of the paddle. Sometimes just moving the boat in reverse once or twice can free up the paddle too.

The B744v Ron mentions came with a blanking plug which is supposed to be secured right near the inside of the T/D. It has the same O-rings which can be used as spares for the B744v speed/temp insert if needed, but when I had the B744V and changed out the insert a couple times over a lot of years I had no problem with damaged O-rings. Just use silicone grease. And have a helper onboard is case you need something you forgot to bring into the bilge with you when water is coming in at a controllable rate.
 
Yes I do have the plug on a short cable nearby. Does the wheel pop out after removing the pin and nut on top of the T/D?
Thanks Ron and Sandy for your help and suggestions.
 
The insert which houses the paddle wheel and temp sensor look essentially just like the plug but has the paddlewheel at the end. Once you remove the pin and unscrew the nut cover the insert may or may not come out easily depending on the amount of silicone grease previously applied. Even if it resists it ...shouldn't... be too hard to pull it out. I can't recall if there is a tongue and groove affair so it only goes in or out facing 1 direction, or if you can twist it when pulling out. Check to see if there is a clocking arrow pointing forward. And check the replacement paddles to see if they are cupped so that side would face forward.

I don't remember the times I did it being very hard. But just be aware , the flap valve in the remaining stem substantially slows water inflow , it doesn't stop it. So be ready to insert either the plug or replacement or have a rag in a plastic bag or similar to press down over the hole to "plug the dike" while you do whatever needs to be done with your 2nd and 3rd hands.

If there is anything nearby you don't want to get wet, pre-plan to protect it just in case. :D

Airmar instructions.:
http://www.airmar.com/uploads/InstallGuide/17-207-02.pdf
 
quote:

Originally posted by Sandy

The insert which houses the paddle wheel and temp sensor look essentially just like the plug but has the paddlewheel at the end. Once you remove the pin and unscrew the nut cover the insert may or may not come out easily depending on the amount of silicone grease previously applied. Even if it resists it ...shouldn't... be too hard to pull it out. I can't recall if there is a tongue and groove affair so it only goes in or out facing 1 direction, or if you can twist it when pulling out. Check to see if there is a clocking arrow pointing forward. And check the replacement paddles to see if they are cupped so that side would face forward.

I don't remember the times I did it being very hard. But just be aware , the flap valve in the remaining stem substantially slows water inflow , it doesn't stop it. So be ready to insert either the plug or replacement or have a rag in a plastic bag or similar to press down over the hole to "plug the dike" while you do whatever needs to be done with your 2nd and 3rd hands.

If there is anything nearby you don't want to get wet, pre-plan to protect it just in case. :D

Airmar instructions.:
http://www.airmar.com/uploads/InstallGuide/17-207-02.pdf






OOPS! :DSooo sorry, all the above was for the B744v that Ron mentioned and I was "off to the (wrong) races" .

Here's the ST50 kit:
https://www.ebay.com/p/Autohelm-St5...it-Airmar-33-112-Raymarine-A28106/21014884996
 
Dodged another bullet. Luckily three weeks ago the wheel started rotating because all is working again.
 
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