Depth Sounder fluid?

[pete32]

Hello
My depth sounder started to only work on a starboard tack, chased all the connections and still nothing, opened up the sender unit and found some liquid in it, not thinking I cleaned all this up then thought afterwards that maybe this liquid was important as a conductor between the unit and the hull.
Was I right to think this? Does anyone know what the liquid is so I can fill it up again?
Cheers!

 

[lexi]

Water works ok but other than that it may be a silicone fluid.

 

[eastcoastbernie]

Some people put liquid in. Some don't. I don't. Works perfectly well without.

 

[RestlessL]

You need something that (1) doesn't evaporate too quickly (2) doesn't absorb air bubbles and (3) won't freeze.

A light mineral oil will do, as would olive oil. Airmar recommend propylene glycol which chemists sell as KY lubricant.

J

 

[simonfraser]

stick it down with a blob of silicone without air bubbles

 

[PCUK]

It used to be castor oil but was later found that simply sticking the transducer to the hull work equally well - see above.

 

[maxi77]

There usually is a significant impedance mismatch between echosounder transducers and air, hence the liquid filled container. Water is fine, the sound is intended to get into water as it is, but mat use castor oil because it does not evaporate. I have used water mainly as it works and is cheaper.

 

[oldsaltoz]

Transducers are fitted in oil baths so they can swing and point to the bottom and display the depth below the hull even when heeled.

You can use water or oil, we used baby oil, but just about any oil will do, it only has to keep the air from the bottom of the transducer.

Hope this helps.

Avagoodweekend......

 

[Lakesailor]

I used chain saw oil

It's fairly thick

I had some.

 

[aitchw]

[ QUOTE ]
Transducers are fitted in oil baths so they can swing and point to the bottom and display the depth below the hull even when heeled.

[/ QUOTE ]

The moulded in cable on mine is so stiff trying to get the thing to swing would be a major headache. Don't know anyone who bothers.

 

[maxi77]

[ QUOTE ]
Transducers are fitted in oil baths so they can swing and point to the bottom and display the depth below the hull even when heeled.

You can use water or oil, we used baby oil, but just about any oil will do, it only has to keep the air from the bottom of the transducer.

Hope this helps.

Avagoodweekend......

[/ QUOTE ]

So your transducer is in a bath that will allow it to roll 45 degrees each way? AS I said it is all to do with accoustic impedance mismatch hence the need to get rid of the air whcih can be done with a number of fluids.

 

[bobgosling]

[ QUOTE ]
Transducers are fitted in oil baths so they can swing and point to the bottom and display the depth below the hull even when heeled.

[/ QUOTE ]

I'm afraid you have been misinformed. Signal is like the wide beam of a torch, hence still accurately detects the correct depth even when heeled.

Baby oil works well, doesn't freeze or solidify. Doesn't react with the plastic and smell nice if accidentally spilled.

 

[Skylark]

A quick trip to the Chemist. Glycerine oil is recommended, from memory.

 

[moody1]

Castor Oil from local chemists - you can buy it in 100, 200ml bottles so buy 2. Keep one as spare to top up later.

Castor is used as it is a good compromise density between water and GRP to provide amn airless connection. The gaff about swinging in the tube is bunkum as most tubes are only slightly greater ID than the transducer head anyway. Castor is also an environmentally acceptable fluid.

 

[EdEssery]

Better than a liquid is a gel. I used Camcare Ultrasound Gel - same stuff doctor uses when he/she is doing an ultrasound scan. It's designed for the purpose and is available through a good pharmacy or on-line.

Ed

 

[grafozz]

just pour olive oil in there , works fine and they,ll be some in your kitchen !

 

[Athene V30]

Had same problem and used ordinary cooking oil as it was to hand. Works fine now.