In hull depth transducer

[Soong]

I have trawled through (I hope all) the postings about drilling a hope for a depth sounder, but I was hoping for a top tip for fitting one to a hull that has no level surfaces.

Any suggestions would be very well recieved, as even the local boatyard is a bit lost. They have suggested building an area up with glass, but that seems a bit over the top. Should I just accept that my depth reading is taken at an angle , rather than straight down?

Cheers.

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[npf1]

why don't you install it inside (vertically) the hull. I read somewhere (respectable!) how it can be done using some plastic pipe attached to the inside of the hull. The pipe is then partially filled with oil and then the transducer immersed in the oil and the whole unit sealed. I seem to recall that this works with most modern GRP boats but soemtimes does not on older boats which tend to have thicker lay ups.

Hope that helps. I'll try to remember where I have read it and send you the article

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[paulburton44]

Can I add my own question ???

What oil should i use for the transducer pot !!!!!!! ?

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[Soong]

That sounds like a plan. Would epoxying it to the inside of the hull do the same trick?

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[npf1]

Can't remember! And racking my brains to think where I read it. It may have been Sail Magazine in the USA.

<hr width=100% size=1>Have boat. Will travel. Maybe cruising in 2005 - wanna join me?

 

[npf1]

the article specifically mentioned not to epoxy the transducer to the hull

<hr width=100% size=1>Have boat. Will travel. Maybe cruising in 2005 - wanna join me?

 

[Spyro]

Try <A target="_blank" HREF=http://www.echopilot.com/infopage.asp?infoid=148>HERE</A> for info.
I have read somewhere that castor oil should be used in the tube. I use ultrasound gel, the kind used on pregnant womans bellies- it hasn't needed topping up in two years of use ( the tube not the belly) You may have difficulty finding some over the counter though.

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[npf1]

do a google search. I found this http://www.echopilot.com/infopage.asp?infoid=148

<hr width=100% size=1>Have boat. Will travel. Maybe cruising in 2005 - wanna join me?

 

[bruce]

cooking oil, water, mineral oil, if using water, must watch for freezing. systen as diagramed works just fine. problems may come from a thick copper bottom paint causing a 'metal' skin over area transducer looks thru. if this is a problem, clean that small area and cover with non copper bottom paint.

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by bruce on 03/12/2004 21:00 (server time).</FONT></P>

 

[machurley22]

The ultrasound gel sounds like a good idea, won't slop around, slow to evaporate probably and specifically designed for the transmission of ultrasound. If anyone has difficulty getting some there's one called Camcare ultrasound gel (they also do an ECG gel and cream so don't get confused) which comes in 150g tubes and most chemists should be able to order it for you.

No connection etc., just some knowledge of the trade.

Dave

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[ashley]

Also from VDO's instructions

An internal installation of the echo sounder is only possible on ships with a fiberglass reinforced hull. This does not apply to fiberglass sandwich hulls.
Due to signal damping the internal installation may cause power losses, and is prone to more disturbances. Check that the location of the installation has no air inclusions in the laminate, and that the hull material thickness does not exceed 12 mm.
The ship must be in the water during the search for the optimum echo sounder location.
Proceed as follows in your search

Put the sender in a plastic bag filled with water and move it over the hull until you obtain a stable depth reading.

It then goes on to state you can fix the transducer to the hull with waterproof sealant making sure there are no air bubbles

the file is <A target="_blank" HREF=http://www2.vdo.com/vdo/sycomax/files/504713_OLdepth_e.pdf>here</A>

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[geoffatstanpit]

Just push the transducer vertically into a wodge of BluTack. Works a treat.

Geoff

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[Talbot]

several companies will provide a kit for their transducers to be fitted in-hull rather than through hull. This includes the Raymarine 60 series, but this one is not recommended for a steep angle. I fitted a Silva dataset in my boat. The in hull kit included a piece of "drainpipe" which required cutting to the correct angle, plus a kit to fit a normal through-hull fitting inside the drainpipe. I attached the pipe to the hull using a tube of plastic padding marine epoxy, but make sure that you have the tube well wedged, mine moved a bit.

My old log used mineral oil as the transmission medium. this works very well, but any leaks create a lot of mess inside the hull. Silva recommended use of water with some anti-freeze added. works for me!

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[kunyang]

Why, when the Isle of Wight hover craft goes within a hundred metres of so does my depth gauge read zero. It's very thought provoking.

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[john_morris_uk]

Of course you haven't said if your hull is suitable for an 'internal' transducer. If transducers are fitted through hulls, the usual method is fairing pieces inside and out. If you wonder round a boat yard you will see a few examples. The outside one is often a sort of short fat cigar shape, but with the hull profile on the top and the bottom flattened to take the transducer.

As it happens none of our boats have had internal transducers - they've been all fitted throught the hull by the time we've got the boat. Some have needed fairing pieces, some haven't.

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[robind]

Do be careful with the fairing piece method as the, through hull, Silva doesnt have a very long threadded bit and you may have drilled your hole and made your fairing bits only to find that you need a longer threaded piece, which they dont do. also dont cut the wire as its a measured length. (teaching you to suck eggs?)
Regards
Rob

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[Soong]

Not at all, my egg sucking needs a bit of polish!

I like the sound of blue tak...

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[seemore]

for internal fitting and assuming GRP hull, the trick is to use something that will avoid an airgap between the transducer and the water outside the hull. I have used this method on 3 different boats - first used oil in a tube (kit provided by manufacturer). Second (after oil leaked from previously installed tube) used waterproof mastic in tube. Third (this was a temporary solution until end of season after failure of through hull transducer) used a plastic pill container filled with water and stuck to the hull inside with mastic; lid was also sealed with mastic to prevent evaporation of the water.

For choice use oil in a bonded in tube - but make sure the bonding to hull is excellent - if you get a leak, as happened in my second boat, not only will the transducer stop working but you will have an oily mess to clear up.

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[ashley]

I always have oily messes to clean up so would not notice!
Benefits of old wooden boats

<hr width=100% size=1>A truly wise man never plays leapfrog with a Unicorn

 

[simonfraser]

nasa do an in hull kit as well, v helpfull chaps on the phone too
filled with oil, air is the problem,
fitted mine on hull at least 18mm thick, works fine till at least 20m

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