muddy tranducers

[perlonious]

hello one and all ........
im new to sailing and last time i went down to my boat my depth was showing intermitenly. i am on a semi tidal mooring on the hamble ...so loads of mud!
i have been told that i will need to take out the tranducer in the bows and quickly plug it. clean it up in fresh water and put it back.its a ST40 system, i was told to do it at low water...but surely all the mud will force its way up and how do u force the tranducer back against the mud? if this is the only way...apart from lifting out ...then how much mud am i likely to let intot he boat...asuming i can get the plug back in quicky?

any other way of doing it???

many thks...to one and all...

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[Trevor_swfyc]

Silly question but are you sure the transducer passes through the hull?

As the mud would soon wash off if the cause was mud, more likely barnacles if the transducer passes through the hull, can you not reach the transducer from outside the boat with a broom but take care not to fall out of the tender sorry if that sounds patronising.

If the transducer is in a tube in the boat and does not pass through the hull top the tube that holds the transducer up with 10 ml of castor oil. Another point it will give erratic readings once the river water level falls outside its detection range.

Trevor



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[tillergirl]

I am a little confused but then that is the normal state of affairs. Usually only the speed transducer can be withdrawn from inside the hull but you say your problem is with the depth side. I have a combined bronze transducer from which the speed transducer can be withdrawn for cleaning but the depth transducer is in the fixed part. My first thoughts would not be to blame mud. I used to dry out on east coast mud for 18 out of 24 hours for nine years and not once did I get a problem with the depth reading because of mud on the face of the transducer. When I had the system before the ST, I did get a problem with some muddy bottoms with the system failing to give a reading but this was because the gain on the system just couldn't cope, if you adjusted it to get a reading where it was getting poor reflections, 20 yards further on it would find a goog patch and go crazy because of the signals bouncing back and forth. When I changed to the ST with its auto gain all this went away.

If your transducer goes through the hull, I would suspect you may have growth on its face. At low water you need to get under the boat, clean the face of the transducer very carefully so as not to damage it and then put a thin coat of anti-foul over it. If your transducer is inside the boat it must sit in an oil bath inside its tube. Any air will give you problems as it will affect the signal to and from the transducer.

If you do have an transducer than can be removed from inside, I would suggest you don't remove it while sitting on the mud. The mud will force it's way in however deft you are. Better to cope with the jet of water of doing it while the tide's in - hand over tude once you removed the transducer. Most do have a blanking cap to screw on while doing this. You will get an armful of water but it is a lot better than an armful of mud! Some ST speed transducers have some flaps inside the tube which cut off most of the water coming in but I wouldn't want to rely on them to stop mud - the whole thing will get pretty gungy.

Hope this helps

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