Datamarine Nylon transducer weeps?

[downeast450]

My old Datamarine instruments are still in their original locations both instruments and thruhulls. I re-bedded my old transducer last winter when I was replacing my raw water thruhull. The fairing was cracked and I wanted the integrity of a fresh mount. I was hoping that cleaning wiring connections might restore the intermittent readings I was getting from the depth sounder. What I discovered is the Nylon transducer itself seems permeable. In the "cup" above the transducer itself, that is the extension of the thruhull's threaded mount, I get salt water! Not much but enough to eventually fill that "cup". I keep a paper towel stuffed in there to soak it up and replace it once every week or so. Probably a cup of water over the entire season is all that I collected. Any salt water entering the hull is cause for concern but this can only be coming through the Nylon plug itself. I think? I am almost positive. Can the Nylon be that permeable?

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[PaulinVictoria]

I read somewhere (on here?) about a transducer just disintegrating, or being almost at that stage. If it's leaking I would say it is probably on its last legs and personally I'd put in a new one rather than risk it.

[lancelot9898]

I would suspect the leakage to be coming from the O rings assuming it's a removeable transducer. My 25 year old transducer experienced some strange damage here recently as noted in another post.

[downeast450]

Yes, I will either find a replacement transducer or remove the old Datamarine stuff. I was keeping it as back-up to new instruments I have installed. It is not an O-ring plug type install. It is a threaded plug with a flange. I suppose water could be getting through following the threads but I sealed them well. If it were threads the water would be collecting elsewhere. It seems to be coming from the wire that exits the transducer. I have never heard of this before.

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[lancelot9898]

Since airmar makes most if not all of the transducers for the various electronic companies, I'll probably shoot an email off the them to see if they have heard of any problems with age. I just wish that I had taken a picture of my problem rather than having to rely on a verbal describtion. The new transducer that I installed this past week makes mention of not using ketone base anti fouling paints on it. Not sure how that reacts with the material and if there is a possibility of more degredation beyond signal loss.

[downeast450]

I sent a copy of this question to Datamarine. We will see if it gets a response.

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[downeast450]

Here is Datamarine's reply.

Hello George,

The water is seeping through cracks in the adhesive of the transducer, not
the plastic itself. This will also interfere with the operation of the
transducer since it will corrode the contacts inside. Your transducer is
most likely the DX-111 (or A-111 depending on the age). The replacement is
the ADX-210($160) and has a 2" thread diameter so it will fit in the same
hole left when you remove your existing transducer. You can see this
transducer on our web page listed below under the PARTS page.

Back then the transducer assembly consisted of a crystal glued inside a
plastic cup, inserted in the housing and filled with epoxy. The water is
seeping between the glue holding the cup inside the housing and finding
it壮 way to the top of the epoxy. It is not the way you mounted it, is all
internal to the transducer.

Steve

My thanks to Steve and Datamarine for his prompt help. Now I understand where the salt water is coming from. Time for a replacement.

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[lancelot9898]

Originally Posted by downeast450

Here is Datamarine's reply.

Back then the transducer assembly consisted of a crystal glued inside a
plastic cup, inserted in the housing and filled with epoxy. The water is
seeping between the glue holding the cup inside the housing and finding
it壮 way to the top of the epoxy. It is not the way you mounted it, is all
internal to the transducer.

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Seems for leakage to occur then the glue must be in direct contact with the water?? I read this as saying that the glue is inside a plastic cup and for leakage to be happening then the plastic must be failing allowing the water to come into contact with the glue?? Pus I'm not sure how the epoxy get added and if that is an additional barrier to the water.

I submitted my question both to Raymarine and to airmar about transducer deterioation with age. I'll post if I get a good answer.

[lancelot9898]

Here's the response from Airmar:

It sounds like some of the epoxy or urethane that constitutes the acoustic window of the transducer has pulled away. I've not heard of that happening in the way you have described, but since there is a ceramic element physically vibrating within the encapsulation material, perhaps after so much time, the material has become delaminated from the ceramic and the material weakened. It's possible I suppose but impossible to say for sure. I can say that although the transducer may work now, it would probably soon have developed a water path into the internals which would cause the transducer to fail. I think you made a wise choice replacing the transducer when you did. Thank you for the update on your transducer by the way. We take pride in what we build here at our factory in New Hampshire and it's gratifying to know that our product has served its owner well over the years.

Best regards,
Airmar Support/Sales

I think it's interesting that the ceramic element is physically vibrating within the encapsulation material.

[downeast450]

Interesting? stuff from Airmar.

The transducer that is "weeping" appears to be a solid mass with an outer face made of different material than the casing that mounts it in the hull. The plastic casing, perhaps Nylon, must be allowing tiny amounts of water to seep between the internal mass and its inner wall. That moisture is working its way up the transducer and appearing on the inner surface of what does look like a poured filling of ? epoxy. I can't see where the moisture is "arriving". The inner surface of the poured top of the transducer is shiny and looks, in the poor light, to be unbroken.

Since I am replacing it and it is junk I may cut it up for closer inspection. That will be a few weeks away since Tundra is still on its mooring in Seal Harbor. Perhaps I can get Mainesail to have a look at it.

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