Inhull/thruhull Depth Sounder

[Amp1ng]

Hi All,
I’ve noticed my depth sounder has developed a disinterest in updating its display since the beginning of this season. It started off updating readings a couple of times an hour (flashing in between) then reverted to displaying 0 for a couple of days but now it seems to have picked up a bit and updates what I consider to be a believable reading on average every few minutes.
I immediately considered replacing the transducer (it’s an old Stowe unit) but on initial investigation I couldn’t confirm whether it was through hull or not. There looks to be a skin fitting and the transducer has a lock nut threaded onto it which bears down on the inside of the hull/skin fitting. If I remember rightly on the underside of the hull there appears to be an almost flush fitting dome shaped cap , is this the transducer head with a flange that butts up to the outside of the hull retained by the lock nut on the inside? Or is this a closed skin fitting into which the transducer is bonded or immersed in an oil reservoir?
Before I go disturbing all this lot is it likely that this year’s antifoul layer (cruiser Uno) has caused the problem in the first place?

 

[agurney]

Before I go disturbing all this lot is it likely that this year’s antifoul layer (cruiser Uno) has caused the problem in the first place?

No.

 

[rob2]

Obviously with you working from memory, it is unlikely that anyone can give you a definitive answer. You could visit the Airmar website and take a look at the various types and styles of transducer and that might answer your question. Alternatively a couple of photos from different angles would help a lot. Although most depth sounders are originally sold with one standard type of transducer, many applications demand a different design to cope with hull shape, material, etc.

If you have only one coat of Uno on it, it is unlikely to have much effect. A build up of ten years' worth might block the signal, though...

Rob.

 

[noelex]

Sounds like a conventional thru the hull depth transducer you are describing. Try cleaning and remaking all the electrical contacts.
Measure the diameter and when you replace it with the same size to avoid changing the hole. I would replace the whole lot display etc. if you buy a new unit now it will probably work inside the hull untill your next hallout (providing the boat is not wood or cored fibreglass )
Air bubbles under the antifouling can slightly degrade the performance, but not the extent you describe.
Listen closely for the clicks if they stop it shows it's definatly defective, but I think you can assume its gone to depth sounder heaven.