Selecting The Best Location - Interphase Proble Operation Manual

Suggested Thru-Hull
Transducer Locations
Fin Keel
~ 1/3 L
L = waterline length
Displacement Hull
Thru-Hull Transducer Installation
The thru-hull transducer is the recommended choice for
larger boats with in-board engines. Thru-hull mounting is
usually required on larger power and sail craft in order to
find a mounting location free of forward looking hull
obstructions. The Probe must have a clear view of the
water ahead as it can not magically see through obstructions
such as the vessel's hull. Please read the following
carefully before starting the thru-hull installation.
Normally, thru-hull installations are performed by a
professional in a boat haul-out facility. We suggest you
seek professional assistance before attempting to mount this
transducer.

Selecting the Best Location

The best location to mount the thru-hull transducer will
vary with the type of boat. Try to find a location with the
smallest dead rise angle to make installation easiest.
a. On displacement hulls (sailboats, trawlers, etc.) locate
the transducer about 1/3 aft along the waterline. Generally
this provides the best compromise between obtaining
aeration-free water and minimizing propeller noise. The
Probe's transducer can not see through aerated water and
water near the bow and near the keel can be quite aerated.
Aeration of the transducer can be minimized by keeping the
transducer mounted away from the keel and by not
mounting too far forward.
b. On sailboats, the transducer should be mounted where
the acoustic beam will not be shaded by the keel. A spot
forward of a fin keel is usually best. Try to find an
accessible spot with a minimum dead rise angle.
c. On planing powerboat hulls, the transducer should be
mounted well aft and close to the keel to insure that the
transducer is in contact with the water at higher boat speeds.
d. Mount the transducer on the side of the hull where the
Planing Hull propeller is moving downwards. The upward motion of the
propeller generates pressure waves and pushes bubbles up
against the transducer's face causing a loss of signal.
On I/O's, transducer mounting close to the
engine usually yields good results.
On inboards always mount the transducer
well ahead of the propeller(s). Turbulence
from props can seriously degrade perform-
ance. (Thru-hull installation is recommended.)
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