INSTALLATION TIPS FOR TRANSDUCERS
SAILBOATS:
The preferred position of the transducer is where water is diverging around the hull and is free
from turbulence and eddies. This is generally in the forward one- third of the hull in front of
the keel and approximately one foot off the centerline. Generally the knot meter transmitter
can be mounted on one side of the keel with the depth transducer in a similar position on the
opposite side of the keel. If due to access considerations, it is necessary to locate the depth
transducer and the knot meter transmitter on the same side on a fore and aft line, be sure to
locate the depth transducer forward of the knot meter transmitter so that the turbulence
created by the paddlewheel does not interfere with the depth sensor.
The depth transducer should be installed in a fairly flat area where the degree of angle does
not exceed 20 degrees (you can use fairing blocks to accomplish this). An alternate location is
along side the keel two feet away and ahead of amidships.
The thru hull fittings require a 2 1/8" hole with a 30 degree flange. SR Mariner provides a tool
(THT) that drills and flares this hole in one operation. If this tool is not available locally
contact the factory and arrangements can be made to rent one (the THT tool requires an 1/2"
drill motor).
NOTE: The thru hull fitting should already have an o- ring installed.
INSTALLING THE TRANSDUCER
THRU HULL:
Choose the location of the sensors and cut your holes for the thru hull fittings. File a notch
FACING FORWARD to seat the key way. The key way ensures proper orientation of the sensors
for use and/or maintenance. After proper fit is secured, place bedding compound around the
lip and body of the fitting where it will be in contact with the hull. Insert the thru hull fitting
and tighten the fitting nut by using a spanner wrench or tap with a small wooden block against
the nut to provide a snug fit. DO NOT OVER TIGHTEN!
CEMENTED TO HULL:
If your primary importance is for shallow water monitoring, the transducer may be cemented
to the hull thereby eliminating a need for a hole through the hull. The position selected must
not have air voids, balsa fillers, etc… It is best to choose a location and make a small putty
dam and fill it with water and put your transducer in it to see if a stable depth is indicated (the
boat should be afloat and the transducer face should be wetted before inserting into puddle).
At this point back off on the gain until reading becomes unstable to see how much reserve
gain is available. Compare this gain setting with the transducer hung overboard; this will give
an approximation of attenuation at the chosen location. If operation is suitable, clean the
surface of the transducer with lacquer thinner to remove the anti- fouling paint. Clean the hull
to remove grease and mold release. The transducer may now be cemented with epoxy or
fiberglass resin (stir the epoxy slowly to avoid air bubbles). THERE SHOULD BE NO AIR
BUBBLES IN THE ADHESIVE BOND.
