Echo sounder problems

[vseager]

Hi there,

I'm new to yachts, this forum and marine electronics. I have recently bought a Cobra 750, it has a Clipper Duet depth sounder/log which isn't behaving correctly. I'm quite sure the speed transducer just has some seaweed tangled up in it, as this seems the most common cause... I will purchase a blanking plate so that I can clean it without sinking the boat.

I'm hoping someone can offer me some advice with the depth sounder though, it is definitely reading incorrectly, I have taken the boat to areas which are 15m deep according to the chart, but the echo sounder is reading only 3 or 4 metres, when moored or in shallower water it seems to read more sensible figures, but in any case it will keep flashing up with the work 'Out' every now and again, which according to the manual means the signal from the transducer is lost.

Being very unfamiliar with these setups I was hoping for some advice before playing around with it as I'm not sure how it is mounted, I know then can be through hull or in hull. From the thread below I am fairly sure it is mounted in hull, and it may be that I just need to top it up with oil, but I just wanted some reassurance before messing about and sinking my boat!
http://www.ybw.com/forums/showthread.php?t=259394

Here are a couple of photo's of my transducer, is it safe to presume that it is mounted in hull and by pulling it out I'm not going to open a hole in my hull?!

Thanks in advance!

 

[alan_d]

Yes, this is the standard oil-bath setup, and you are probably low on oil.
I believe you are supposed to use castor-oil, but I have found cheap cooking oil to be satisfactory.

The transducer is mounted on the white plastic "lid", lift that off and pour some oil into the white plastic pipe which is fixed to the inside of the hull. Don't overfill it or it will overflow and make a mess when you replace the transducer.

 

[VicS]

As above

Be sure not to trap any air bubbles under the transducer when refitting it.

Instructions for the Seafarer transducer in the thread you post a link to apply equally to the Nasa one.


The tube does not look very securely bonded to the hull !

 

[vseager]

Thanks for the replies. I'll try topping it up with oil. Do the transducers fail very often?

 

[Vara]

Thanks for the replies. I'll try topping it up with oil. Do the transducers fail very often?

I've never had one fail, and it's not a recurring theme on here so I guess not.

Installation problems though are another matter.

 

[Bru]

Don't worry too much about the occasional "Out" flash as long as you're getting valid readings the bulk of the time. Ours does the same thing from time to time whenever we hit a turbulent bit of water or similar

The incorrect readings though are more of an issue. Dunno about oil bath mounting 'cos we simply fitted our transducer onto the hull bottom with a big glob of Sikaflex and it works just fine

The log on the other hand is rather less sucessful. With an impecabbly clean impeller and no weed or barnacles anywhere near the impeller housing on the hull and the gain cranked up to it's maximum of 150% the log reads something vaguely close to our actual speed through the water on a really good day! Most of the time it reads pessimistic which I can live with as it's really only a sail trimming aid (as in "did that make us faster or slower?") but now she's picked up a bit of a weedy bottom it barely reads anything at all