3: ECHO SOUNDER
3:1 INSTALLING THE TRANSDUCER
The transducer can be mounted in one of three ways:
(a) The transducer face can be bonded directly to the inside of the hull.
(Some energy is lost to the hull but the loss in performance is, for
most G.R.P, hulls, hardly noticeable).
(b) A transom mount is available from your dealer.
(c) The transducer can be positioned inside a GRP hull by means of an In Hull
Transducer kit.
This method of installation has the dual advantage that no hole is made in the
vessels hull and that the echo sounder and transducer can easily be removed for
examination or installation elsewhere. It should be mentioned however, that
although the accuracy will in no way be affected by installing the transducer
inside the hull, the maximum range sensitivity may be reduced, depending on the
thickness and quality of the glass fibre. The In Hull Kit is available direct from
NASA Marine or your local chandler. Whichever is selected the best location still
has to be found.
Select a position below the water level where the transducer will point substan-
tially towards the sea bed and where the transducer and cable are kept well clear
of interference generating equipment. This position should be well clear of large
masses of bubbles or cavitation which would disrupt the signal.
To test the suitability of the location, press a little sticky chewing gum on the sur-
face of the transducer and stick it down to the inside of the hull (remove dirt and
oily residue first). The unit can then be tested. If the location is
satisfactory the chewing gum can be removed and the transducer mounted
using one of the methods described previously. (Note: Do NOT shorten the trans-
ducer cable).
It is important that the face of the transducer is thoroughly bonded down to the
hull. A single air bubble will cause a considerable loss in performance.
The transducer and the place of mounting must be kept entirely free of any
antifouling compound as this can also effect the performance of the unit.
