Depth Tranducer

[BobE]

Hi Gang, just a short one which you might be able to help on..
I'm fitting a new depth instrument in the old girl and there seems to have been a transducer glued to the inside of the hull in a forepeak locker..
It was, I assume, broken off. So the same thing might happen again.
I suppose I could haul her out and drill yet another hole in the fibreglass hull but I'm not keen
So what about glassing in the transducer holder and then a tube similar to a malt bottle box but shorter, and then putting some liquid in the tube and holder so the thing works... it wouldn't when I held it on to the glue from the original ??

As always any comments welcomed

Cheers Bob E.

 

[rogerroger]

I'm tackling a similar problem this weekend. Mine is housed in an "inhouse transducer kit" - basically a plastic toilet roll inner that bonds to the inside of the hull, is filled with vegetable oil or castor oil in which the tranducer sits.

The advantage of this is that you can take it out to inspect it. I've considered going through the hull but don't fancy drilling another hole!

I'm having to re-fit mine as the seal was not sound so the oil leaked out and I lost signal.

Roger Holden
www.first-magnitude.co.uk

 

[billskip]

Hi Bob..You should get info with the new one..fitting thro hull is best ..but most are fitted as roroger says..you can "glue direct" but its necessary to make sure there is no air bubbles hence the oil method.. they will only work if no air is between it and the ground so sometimes false readings when going fast due to air bubbles under hull...

Bill
www.aegeansailing.co.uk

 

[Deleted User YDKXO]

Some manufacturers eg Autohelm have a ready made in-hull fitting kit which consists of a tube in which the trandsducer sits normally immersed in castor oil. You can make your own tube but you need to have some means of locating the transducer inside it and a cover to stop the oil leaking out. On my boat the tube is fixed with silicone filler but it can also be glassed in
Its best to experiment as to the optimum position for the transducer and this can be done by connecting up the transducer and placing it inside a water filled plastic bag and moving it around the inside of the hull until steady readings are obtained

 

[BobE]

Thanks for the prompt ( very) replies.
I think I'll bond the thro' hull fitting inside the hull and then an outer case ( got to get rid of those damn malt whisky tubes) outside that for protection. .I guess I'll have to drill a very small radial hole in the housing just below the lower "O" ring level then any air should be forced out when I insert the transducer This would mean that I can still move the thing elsewhere if performance is not good enough. Has Caster oil any significance? What about a light oil like Redex. (We used that in a plastic tube from the bows thro' one set of limber holes to aft the mast for fore/aft trim in my racing days and I don't think it evaporated..)
I sail from Christchurch and she's a Sadler 32 with a liftiung plate but still draws 3' 6" and keep hittin' th' mud..
Cheers Bob E
Bob Egerton ( In the New Forest of good old England )
(0) 1425 655712
r.egerton@virgin.net

 

[Guest]

Bobe see your private mail - also all this 'in hull' stuff only works if the hull is not of sandwich construction.

 

[Guest]

Rodger,
Did mine recently as follows.

Use blue tac stuck on transducer end to find suitable spot. Push hard for good contact!
Clean up hull in chosen spot with coarse grit paper and wipe clean with white spirit or something similar on a piece of rag. Safely dispose of rag. No sniffing mind!
Obtain one B & Q 40 mm. domestic waste pipe straight connector(screw type with rubber seals and hand nuts). Chamfer The fitting body to fit hull (Cut end of threaded section away at one end with a hacksaw, leaving body of tube vertical)
Clean up chamfer form with coarse grit paper( lay out paper in vicinity if chosen fixing zone of hull. Rub chamfered face to-& fro on paper carefully. (Couple of inches of movement) to clean up.
Wrap paper tape around top threaded section of fitting to keep the goo off it.
Prop or wedge fitting in position.
Make up some standard fibreglass resin and soak in a few strips of kitchen roll. Apply soaked strips to hull/ fitting interface in "wrap rounds" and tuck in firmly to make primary "hold it" bond. It's easier to manipulate than glass cloth.
When set, use strips of resin soaked glass cloth to strengthen the joint.
When set, paint a drop of resin around the inside of the fitting/hull joint for added security.
Make up a flat plastic disc(o/d to fit in nut)with centre hole to take transducer lead.
Make one radial cut in disc to get the transducer lead in place.
Insert transducer(mine was Nasa) via a suitable off-cut of 40 mm. pipe to hold transducer down, fitting nut, plastic disk and rubber sealwasher.
Pour in the caster oil and tight the hand nut down to secure all the bits.
Hope this helps, it worked for me.
Just read this---not trying to pontificate, just help.
regards
Rod

 

[Guest]

Rodger,
Did mine recently as follows.

Use blue tac stuck on transducer end to finsuitable spot. Push hard for good contact!
Clean up hull in chosen spot with coarse grit paper and wipe clean with white spirit or something similar on a piece of rag. Safely dispose of rag. No sniffing mind.
Obtain one 40 mm. domestic waste pipe straight connector(screw type with rubber seals and hand nuts) from B & Q.
Chamfer The fitting body to fit hull (Cut end of threaded section away at one end with a hacksaw, leaving body of tube vertical)
Clean up chamfer form with coarse grit paper( lay out paper in vicinity if chosen fixing zone of hull. Rub chamfered face to & fro on paper carefully. (Couple of inches of movement) to clean up.
Wrap paper tape around top threaded section to keep off the goo.
Prop or wedge fitting in position.
Make up some standard fibreglass resin and soak in a few strips of kitchen roll. Apply soaked strips to hull/ fitting interface in "wrap rounds" and tuck in firmly to make primary "hold it" bond.
When set, use strips of resin soaked glass cloth to strengthen the joint.
When set, paint a drop of resin around the inside of the fitting/hull joint for added security.
Make up a flat plastic disc(o/d to fit in hand-nut)with centre hole to take transducer lead.
Make one radial cut in disc to get the transducer lead in place.
Insert transducer(mine was Nasa) via a suitable off-cut of 40 mm. pipe to hold transducer down, fitting nut, plastic disk and rubber sealwasher.
Pour in the caster oil and tight the hand nut down to secure all the bits.
Hope this helps, it worked for me.
Just read this---not trying to pontificate, just help.
Regards,

Rod