Poignard
Well-Known Member
I remember reading somewhere that the oil used is castor oil. If that's true, our resident forum chemist might like to explain why that is the preferred oil.
Depth sounder that does not need a hole drilled in boat?
- Thread starter steve yates
- Start date
VicS
Well-Known Member
Yes you can get a kit to mount the Nasa transducer in hull, but not difficult to find plumbing stuff to do the same.
http://www.nasamarine.com/product/in-hull-transducer-mounting-kit/
Here are the instructions https://seamarknunn.com/acatalog/2050228.pdf
My Seafarer transducer is mounted in the same way.
I am surprised your Longbow does not have a Seafarer transducer already mounted in the hull .. It's what Westerly used to supply as an Echo sounder back in those days
If you opt for direct bonding to the hull with epoxy. silicone, Sikaflex or whatever it is important that you do not trap any air between the transducer and the hull.
I filled my Seafarer mounting with castor oil as recommended by Seafarer
Castor oil seems to last forever without going claggy or rancid like some cooking oils will tend to do. Cooking oil will do the trick but I can guarantee that castor oil will not deteriorate inside 40 years . It finds some use as a preservative!
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steve yates
Well-Known Member
It does have a seafarer transducer vic, actually twin ones, and a seafare 
( doesn't work) but I was told that a NASA etc depth sounders transducer wouldn't fit.
I must admit, I assumed they were in skinfittings, is this not necessarily so?
More specifically, can a clipper transducer not simply replace the seafarer one?
Thx.
( doesn't work) but I was told that a NASA etc depth sounders transducer wouldn't fit. I must admit, I assumed they were in skinfittings, is this not necessarily so?
More specifically, can a clipper transducer not simply replace the seafarer one?
Thx.
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VicS
Well-Known Member
It does have a seafarer transducer vic, actually twin ones, and a seafare
I must admit, I assumed they were in skinfittings, is this not necessarily so?
More specifically, can a clipper transducer not simply replace the seafarer one?
Thx.
The Nasa and Seafarer transducers are interchangeable.
It is unlikely that yours are through hull mounted. You would have seen them on the outside of the hull if they were!
Very possibly the Seafarer transducers are OK and would work with a new Nasa sounder. Or if not you should be able to fit new Nasa transducers in place of them. Either way you will have to locate and check the automatic change over switch.
How thoroughly have you investigated the Seafarer echo sounder. Is it 12 volt powered , if so have you checked the power supply ... or is it powered from its own internal 9 volt battery. I think if fitted by Westerly it probably has an internal PP9 battery which might be flat.
I have the instruction book for a Seafarer 3 in my Photobucket account
Try experimenting with this URL to see if you can view it http://s50.photobucket.com/user/Vic43/library/Seafarer 3?sort=3&page=1
or http://s50.photobucket.com/user/Vic43/library/Seafarer 3
You can view the instruction manual for the Nasa sounder on their website
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John the kiwi
Well-Known Member
I bought a cheap and cheerful garmin fishfinder with transom mount transducer.
I stuck the transducer in a wadge of vaseline inside my glass- over-ply hull to try it.
Been there 5 years now. Measures accurately from 400 mm to well over the 150 metres too.
I built a wee box and fixed it so that the transducer doesn't get knocked out of place.
(Retractable keel and rudder. 400 mm is just enough to float.
)
I dont think you really need these fancy oil filled chambers.
I stuck the transducer in a wadge of vaseline inside my glass- over-ply hull to try it.
Been there 5 years now. Measures accurately from 400 mm to well over the 150 metres too.
I built a wee box and fixed it so that the transducer doesn't get knocked out of place.
(Retractable keel and rudder. 400 mm is just enough to float.
)I dont think you really need these fancy oil filled chambers.
Poignard
Well-Known Member
It has preserved me for well over 70 years; I was dosed with it as a child!
(Some here will say it should be banned!)
vyv_cox
Well-Known Member
I don't think there is a chemical preference. The fluid acts as a couplant between the probe and the surface, in this case the boat hull, but many different fluids are used dependent upon the activity, e.g. ultrasound scans on the body, crack detection in metals and many others. Water based gels are used on the body, silicone and paraffin based fluids, gels and greases are used elsewhere. As VicS says, castor oil has a long history of use in boats and seems to last well.
steve yates
Well-Known Member
brilliant, thx guys.
VicS
Well-Known Member
Thats right almost any liquid which is not volatile, will not freeze, is non corrosive, will not attack the hull or the transducer, does not smell obnoxious. and will not deteriorate over many years can be used. Ethane diol (antifreeze) is one I had previously thought of!
In one job many years ago we were custodians of the site ultrasonic ( metal) thickness instrument and consequently did a fair bit of testing. Vaseline or similar was probably the most used couplant because mostly we were looking at vertical surfaces.
John the kiwi
Well-Known Member
Vaseline!
I think that's what i said?
Cheap, available, non irritating(to skin as compared to epoxies), non setting, remove and replace at ones leisure: whats not to like?
Cheers
John
ex-Gladys
Well-Known Member
Castor Oil is very difficult to get hold of these days, as it is an abortifacient. Olive or corn oil will do just as well
chrisclin
Well-Known Member
I just use water - tested various positions as recommended and never got round to replacing it. Let's face it, that's what the thing is designed to fire through!
pvb
Well-Known Member
Water obviously will work, but it will also evaporate, necessitating topping up. Oil lasts longer.
DownWest
Well-Known Member
Olive oïl has a rep of going rancid. We bonded the bit of tube to the hull with Sika 11FC PU adhesive, as the original tube had come off, bonded with Isopon? 11FC is really good, bonds to virtually anything. Johnson's Baby Oïl is in the tube.
DownWest
Well-Known Member
Didn't know that about castor oïl. But difficult to buy because it might be used for 'medical' reasons? Bit nanny state...
Mostly smelt in exhaust gas on race tracks, as very stable at high temps.
Moonbeam
Well-Known Member
Fixed my thru hull Garmin P79 transducer to the hull with plumbers putty (just like window putty) as a temporary to test... it's been there 6 years now... works perfectly, does not go off and is easily removed.
Caer Urfa
Well-Known Member
+ 1 Again , tested position using blue tack as needs to be vertical but away from keel, the after a good dollop of Sikaflex push the sensor down into it to remove air bubbles
and try and support it for 24 hrs so it sets vertically, never a problem in 16 years.
Champagne Murphy
Well-Known Member
ex-Gladys
Well-Known Member
I gave up trying to buy some about 5 years ago for this very purpose... Hence the olive oil...
Beelzebub
Well-Known Member
Not wishing to be negative but I think it is important to point out that an internally-mounted transducer loses a certain amount of gain by dint of having to transmit through the hull. While this doesn't affect accuracy it can have an effect on the overall range of the sounder, resulting in no readings in deeper water. To most sailing people this is immaterial but to those looking to find fish in deep water it is something to be borne in mind.
Of course the huge plus is one less hole in the bottom of the boat, something which isn't to be sniffed at!
Of course the huge plus is one less hole in the bottom of the boat, something which isn't to be sniffed at!