Correct oil for In hull transducer

[Leighb]

Hi,
I have a Seafarer 5 with the in hull transducer fitted. The oil in the "cup" which holds the transducer seems to be very low, what oil should I use to top it up?
The manual states Castor Oil, presumably only available form chemist shop?
Are other types of oil equally OK?

 

[Stoaty]

On previous boats I have used the cheapest cooking oil I could find. It does disappear over time but is cheap to replace. I think I am right in saying that as long as it's thick enough to get no air bubbles in it, as the boat moves around, then it's ok.

 

[Talulah]

I believe mineral oil is recommended. You can buy a scented version as baby oil in most food/chemist outlets

 

[orizaba]

i use castor oil and it is available in the chemist,

 

[graham]

[ QUOTE ]
On previous boats I have used the cheapest cooking oil I could find.

[/ QUOTE ]

I refilled mine "temporarilly" with tescos cooking oil a few years ago.Works fine.

 

[VicS]

Yes Castor oil was commonly used and is what my Seafarer transducer is immersed in. Mine is in a plastic tube glassed to the inside of the hull (but I cannot remeber if I bought a kit or made something up from plumbing fittings).

You need enough oil to ensure that there is always oil between the transducer and the hull and that air bubbles cannot find there way below the transducer.

Almost any liquid that will not attack the hull or transducer, that will not evaporate or freeze will work but if you are topping up an existing installation you should endeavour to use the same as the original to avoid any compatibility problems. I would expect any vegetable oil to be OK with castor oil but some cooking oils seem to go a bit "claggy" with age. Don't mix vegetable oil and a mineral oil.

The most sensible thing to do is to stick with castor oil if you believe that is what is in there at present. It seems to last forever without any deterioration.

 

[Leighb]

Thanks all,
I will get some castor oil as that seems most appropriate.
I guess it will be best to mop out the existing stuff as then no risk of compatibility problems.

 

[BrendanS]

yes, very good idea to clean out as much as possible of old stuff, as you don't want two immiscible oils in there

 

[Stoaty]

[ QUOTE ]
as you don't want two immiscible oils in there

[/ QUOTE ]

I am not going to try it, but I reckon that would not be a problem, so long as there are no bubbles in it.

 

[BrendanS]

If you mix two oils together that won't mix, you can get little globules of one oil in the other, which will have the same effect as bubbles.

 

[2Tizwoz]

The handbook recommends castor oil.

Mine's been sitting in it for 27 years and still works ok so its probably safe to use.

 

[Lakesailor]

I agree with the advice to remove the old oil if possible. Something claggy and mineral is my choice. I used chain saw oil. Seemed to work well and I had a bottle of it.

 

[Guest]

I bought 2 100ml bottles from local chemist ... 1 went into hull fitting - other on shelf as spare top-up. Still there 10 yrs later.

castor oil is advised for various reasons ... a) it is of suitable density to not impede or reduce signal significantly. b) it is relatively thick and any air bubbl;es that are in when transducer is inserted do disperse quite easily. c) it does not attack the GRP or tranducer material - it is an inert compound. d) if it leaks out and is expelled with bilge wtaers - it is biological and not mineral so is environmentally more acceptable.

 

[Martin_J]

I wonder why the oil level is low...?
Is there a small gap between the tube (transducer holder) and the hull.... enough to allow a seepage of oil into the bilge. Check before it leaks all the new oil out. Learnt from experience after topping one up on an older boat. The old oil had dispersed over so many previous years....

 

[yoda]

I have used sea water instead of oil for over 20 years and get a very acceptable reading. It's cheap and plentiful. Also doesn't leave a slippery mess if it escapes from the pot. Try it first before you spend money on oil.

Yoda

 

[MarkGrubb]

Moving away from the oil theme, I've a friend who uses fairy liquid instead.

 

[bobgoode]

Clean it out and slap in cooking oil.

 

[EdEssery]

Best of all is to get a tube of Ultrasound Gel from the chemist. It's specifically designed for the job you are using it for and is a gel rather than a liquid which can run out when heeled etc. Made by a company called CamCare as I recall.

Ed

 

[Guest]

I'm always amused by the variations of what to put in the tubes ... manufacturers say Castor Oil ... easily bought in small bottles in most chemists ...

I assume that many variations come about due to lack of castor oil on board and people grab other liquid as temp solution ... it works and they stick with it.

Only thing about the gel I would be wary of - being thick and less "flowable" - the possibility of air trapped and also heeling of boat - ? I think I will stick with free flowing liquid ... and surely easier to use, and cheaper ?

 

[VicMallows]

Quite often OLIVE OIL is suggested....I assume by people who don't sail in winter. Even indoors in Hampshire it solidifies in winter ... let alone in Latvia.

Anyway, it's fun explaining to the pharmacist WHY you want castor oil /forums/images/graemlins/ooo.gif

Vic