32-3 Knotmeter Transducer

[Mindscape]

Has anyone removed the knot meter transducer on a 32-3 while in the water? If so how did you get to it? My knot meter just stopped working, first it started reading to high (saw a reading of 9.2 knots, was pretty sure I wasn't going anywhere near that fast in 10 knots of wind ) Then it worked it's way down to 0, where it has been for a while.

If anyone has seen similar behavior or has any ideas on how to debug where my problem lies (transducer or the meter itself) I'm open to ideas.

TIA.

 

[Emerald]

What brand and model is it? If it's Datamarine, I have some troubleshooting steps having just done this.

 

[newgringo]

Our E32-3 came with Autohelm instruments and an Airmar ST600 paddle speed tranducer. The transducer is easily removable for cleaning/rebuilding by installing an Airmar plug in the hole. But if you don't have a plug ...........

 

[ref_123]

Transducer

On our boat, the transducer is in the forward-most locker under the port side setee. It is also covered by the rounded rectangle-shaped cover held by some screws.

There was a plug supplied with the transducer, but any smaller tapered soft-wood plug will do just fine.

Be prepared for a small fountain of water as you pull the transducer out (may have to rotate it to pull out - there is some locking mechanics involved). If you are fast with the plug, you will have to deal with only very small amount of water. It should drain to the shower sump behind the mast. Anyhow, have towels ready to go. Finger will do just fine as a short-term solution to plug the hole .

This is not an operation to be nervous about, but it can be messy if you are not quick. I learned it the hard way .

Regards,
Stan

 

[Mindscape]

My Bad...You would of thought...

The instruments on our 32-3 are the Datamarine brand that seem to of come with many of the mid 80's Ericsons. Seems like I would of mentioned the brand name in my first post....

My transducers are both in front of the keel, in line with the most forward being the knot meter and behind it the depth. I can see one of them looking thru the access hatch under the drawers in the vberth. I'll check the port side locker but I don't think thats far enough forward.

Any help on trouble shooting steps would be great!

Thanks for the help guys!

 

[treilley]

Frank, if it is a Datamarine, I can probably get you a free used transducer.

LMK

 

[Emerald]

Hi Frank,

that's what I needed to know before I typed a book. I just went through this with my DMI knotmeter, and after a nice chat with them, I have some troubleshooting steps to follow:

1) Disconnect the BNC (input coax) from the back of the instrument. Take a paper click and bend it into a U so you can put one end into the center of connection on the instrument and then tap the other end of the paper clip on the outside of the connector. The faster you tap it, the higher the speed reads. So, if you get a reading, it's probably your sending unit or in the cabling and your head is OK.

2) if it responds to the above, hook the cable back to the instrument and locate your transducer. From the transducer end, work back up the cable about 10 feet. There's another BNC connector. You can disconnect it, and using the same paper clip (what a versatile tool), short out the center lead to the outer part of the connector by tapping. Again, you should get a speed reading, and the faster you tap, the faster you go. If this checks out, your cable integrity to this point is OK. and you are now down to the sending unit. The sending unit is held into the thru-hull with a large cotter type pin. Make sure you have a blank plug at hand, and remove the pin, gently twist and lift, and see if you can't withdraw the core of the sending unit, of course being poised to put the plug in. Water will come in. You will get wet, but after you've done it 1/2 a dozen times, you'll get used to the shower and cleaning up the mung on it.

Of note, your symptoms are very similar to mine, which required a new sending unit. I would have real readings, and then nothing, and then perhaps .2 and so on.

 

[mherrcat]

Not to hijack your thread, but I am also having a problem with my speed transducer. The transducer works, but seems to be smaller than the through hull fitting. (It hasn't actually been installed since I have owned the boat. There has always been a plug screwed into the that through hull and the transducer was just lying in the bottom of the hull.) I think for some reason the through hull fitting was changed or someone got a different transducer and it was the wrong size.

I measured the plug and it appears to be 3 1/2" long and 1 9/16" wide. I have not been able to find a used transducer at any of the used equipment places I have looked. The transducer that doesn't fit appears to be only about 1" wide.

 

[Frank G]

My datamarine knotmeter isn't working either. I replaced the paddlewheel, which would have a new magnew and that didn't work. I'll try the above suggestions. I hope it works.
Thanks for the info

 

[Frank G]

I failed to mention that I have a 1985 E-32-3. Gotta love that boat.

 

[Mindscape]

Testing to do...

LMK - thanks! and after the testing I need to do with the special paper clip tool I may take you up on it! Thanks everyone for your responses - I'll try the test this weekend and see where I get too.