Airmar Depth Transducer

[petem]

I have an Airmar Depth Transducer (in hull) that seems to be particularly sensitive to the exact level of fluid inside it. If I leave the boat for a couple of months the depth sounder only gives a depth reading for perhaps 50% of the time. If I then empty the fluid and replace with another 72ml of fluid it works again perfectly for a few weeks.

I've been using standard blue antifreeze in it which I doubt is the exact Propylene Glycol that the manual recommends.

Any ideas? Is there a better fluid that I can use? Do I have some other issue, a leak perhaps?

 

[tjbrace]

My previous boat had an in Hull depth transducer (NASA) . I used castor oil in it and never had a problem.

 

[matthewriches]

Strange. The NASA ones I've had to fit for people come with a bottle of "stuff". Our Raymarine supplier gives me a big bottle of "stuff" every now and then and it just smells and feels like baby oil??

 

[rgarside]

I have an Airmar P79 - I put in the recommended quantity of Propylene Glycol and have had no probs since I installed it 2 years ago. I used a silicon sealant to seal the mounting to the hull and I recall there were some comments about the compatibility of the fluid with the sealant. Are there any signs of a leak? I don't think that there is any deterioration mechanism that would affect the acoustic coupling of the transducer to the water outside.

 

[petem]

Thanks all. From reading your responses it seems that Propylene Glycol us a bit more gloopy than ordinary antifreeze so I'll try that (I can get a couple of 100ml bottles from eBay for a couple of £). I'll also check the base for leaks and re-seal with silicone if I'm still losing fluid.

 

[Spirit (of Glenans)]

My previous boat had an in Hull depth transducer (NASA) . I used castor oil in it and never had a problem.

+1. Doesn't evaporate, doesn't damage plastic, doesn't go rancid.

 

[Spirit (of Glenans)]

Strange. The NASA ones I've had to fit for people come with a bottle of "stuff". Our Raymarine supplier gives me a big bottle of "stuff" every now and then and it just smells and feels like baby oil??

Liquid paraffin?

 

[ghostlymoron]

I used Mazola cooking oil in my NASA one. Changed it annually and had no problems. Certainly didn't get any oil with the kit.