Echo sounder problem

[Cohoe]

I have an old echo sounder Nasa target depth instrument I think. Its fitted to my 20 year old Jouet 1040 which is hauled out abroad at the moment. Last year I had trouble getting a depth indication in reasonably shallow water. I cleaned the hull of growth beneath the head, checked the wiring and examined the head. I discovered the head was immersed in an oil bath, I presume to give good attenuation through the hull. I noticed there was some emulsified oil on the head so I cleaned it off. It seemed to work better afterwards. I'm not sure how it works as i don't have a manual but i thought it might be a good idea to clean it out and renew the oil. So does anybody have any experience of this and what oil I should purchase please?

 

[oldsaltoz]

The use of an oil bath is to enable the transducer to point at the bottom when heeled.

The oil is added to prevent any air between the transducer and the hull/external water.

You can use any oil, go for one with a low odour, that is not too thin and runny.

You can stick the transducer direct to the hull, just ensure you don't trap any air when doing this.

Hope this helps.

Avagoodweekend......

 

[Cohoe]

That was very prompt, thanks. So engine oil would do or would the additives attack the plastic. I believe engine oil is 60% oil and 40% additives. Perhaps her ladyships purest cooking oil or extra virgin olive oil it works well for me. ;-). Cheers.

 

[VicS]

I dont know what oil Nasa supply with their "In hull transducer mounting kit", they dont say but Seafarer in their day recommended Castor Oil.

An reality almost any liquid will do provided it does not attack the transducer or the hull or the fitting kit, will not freeze or evaporate, will not deteriorate or decompose or attract insects, bacteria or mould. Castor oil has stood the test of time in my boat.

 

[leomagill]

I use castor oil in mine with good results.

 

[isha]

Castor oil.
Dave

 

[Mariner69]

Fresh water works OK in mine. Just drain it when laying up for winter.

 

[Cohoe]

Thank you everyone. I'll try good old castor oil.

Cheers Cohoe.