In-hull depth transducer

[Sovereign]

I purchased a Raymarine ST60 'Value Pack' (Wind / Speed / depth) to replace my old B&G system which had finally died. The B&G depth transducer was bronze and mounted in a fairing - in order to acheive a satisfactory vertical sending angle (otherwise difficult in my long fin and skeg Sovereign 32).
I now discover that the transducer supplied in the 'Value Pack' is a plastic Airmar P319 which is NOT recommended for use with a fairing block due to potential for damage.
In-hull route: Raymarine's P79 comes supplied with an adjustable housing allowing for up to 22 degrees - BUT the minimum I can seem to find is about 35 degrees!
QUESTION: Am I right in thinking I can simply use a bit of plastic piping to fabricate an 'oil-bath' and fix the P79 (or another compatible transducer??) into it? (I have been down the route of emailing questions to both Raymarine and Airmar who refer me around in circles!! Also - beware seeming bargains - Raymarine will not credit me for the P319 against a replacement, nor will the company who sold me the pack....)
All advice welcome - remembering please that I am not too technical!

 

[rogerthebodger]

Why don't you see if the B&G depth transducer will work with the Raymarine ST60 instruments.

My SIMRAD instruments work with Raymarine ST60 depth and speed transducers.

 

[alahol2]

Your question first... yes, any sensible bit of plastic pipe can be epoxied into the hull to form an oil bath.
I'd agree with the suggestion that you try the B&G transducer first.
I don't see why you could not use the supplied transducer with a suitable fairing block. Most common transducers are plastic and I have had plastic transducers fitted through hull into fairing blocks on previous boats. Don't see any problem with it.

 

[VicS]

Roger Shaw's suggestion the the simplest solution. If the transducers are the same frequency that will almost certainly work.

The instruction manuals should tell you the frequencies, alternatively you may be able to find the info on line. If all else fails, try it to see if it works.

If necessary yes if the new transducer is one with a"stem" bond a length of plastic tube to the inside of the hull, partly fill with a suitable liquid such as castor oil and mount the transducer through a cap or plug in the top of the tube. ( domestic waste pipe)

Almost any liquid will do that does not attack the hull, the mounting or the transducer, is not volatile, will not freeze, does not smell, will not deteriorate over time and will not cause any problems if it leaks out.

 

[colvic987]

i would fit everything , except the transducer and connect the b+g one and see if it works, if it doesnt then either fit the new raymarine one or buy a new bronze one from raymarine, and sell the plastic one to get some of your money back. (but i would be surprised if the b+g one doesnt work).

 

[steveghoward]

Don't know if this will help but NASA do a echo sounder transducer kit which contains everything needed for glassing in an in hull unit. Costs about £15. Not worth scrabbling around trying to get the bits yourself in my opinion.

 

[oldsaltoz]

Hi Sovereign and welcome to the YBW forums,

Oil baths are only used to maintain correct depth when heeled, most sounders today have a wide beam and the oil bath is not needed.

You can stick the transducer direct to the hull with Sikaflex or other suitable sealants. the trick is to have a good dollop of sealant with a slight peak, place the end of the transducer on the peak and rotate as you push it down, this should eliminate trapped air.

Before you do this, put the transducer in a plastic with some water, wet the hull to eliminate any air gaps and move the bag around to find the best signal, avoiding any irregularity in the hull structure.

Hope this helps.

 

[crossbones]

In hull transducer.

Oil pots are not there to "maintain correct depth" but to ensure good acoustic coupling
with the hull. Most transducers have a beam angle of about 40 degrees.That is plus and minus 20 degrees from the vertical. If you mount the transducer at an angle of 20 degrees then you will be working at the beam adge and will have no margin for heeling. The use of an oil pot mounting kit allows you to mount the transducer vetically, the oil filling the space between the transducer face and the hull.
Most sounders work in the range 50Khz to 200khz. Flexible materials such as sikaflex and silicon rubber attenuate sound at these frequencies so may cause a significant loss of performance.

 

[Sovereign]

THANKS

Thanks to all respondents for input - I have since had another reply from Airmar who have suggested that the transducer supplied for thru-hull should work just as well with the 'bath'. So I shall go down that route. (I shall not try the old B&G, as B&G suggested that the transducer might have an intermittent fault that was blowing the circuit board....).