Thru-Hull - Interphase Sonar Engine SE-200 Operation Manual

Suggested Thru-Hull
Transducer Locations
Fin Keel
~ 1/3 L
L = waterline length
Displacement Hull
SE-200A
This version uses thru-hull transducer (T1-I200-026) which
scans a 12 degree beam from directly forward of the boat to the
bottom. The sketch at right shows the scanning area from both a side
and top view.
Make sure it has an unobstructed view in these directions.
Mount on the centerline or on either side of the vessels keel. The
horizontal beamwidth is 12 degrees, so the transducer can be
mounted within about 1' of the keel without any loss of forward view.
SE-200AVertical Scan
Thru-Hull Considerations
Thru-hull transducers are for boats that exceed 40MPH
and /or have inboard motors. Transducer placement
depends on boat size, speed, hull configuration and sonar
application. On displacement hulls, the transducer is
generally located between 1/3 and 1/2 aft of where the
bow meets the water line. This is the farthest forward the
transducer should be mounted. It is important that the
transducer be below turbulent aerated water created by
the bow and does not come out of the water during
normal operation or when the boat is pitching in a
seaway.
Make sure the transducer has a clear view ahead and that
there are no forward hull obstructions that can cause any
turbulence in front of the transducer.
Mount so the transducer(s) bronze stem is within
approximately +/- 5 degrees of vertical to insure scanning
in the proper directions. Most vessels will require a
fairing block to compensate for the angle (dead-rise) of
the hull.
Special Thru-Hull Mounting Considerations
On sailboats with a fin keel, the transducer is most often
placed at the leading edge of the keel and sometimes
faired into the keel. As this location may be where the
sling rests when hauling the boat, the transducer may be
placed on either side of the hull with the foremost face of
the transducer even with the leading edge of the keel.
Alternatley, the transducer may be placed forward of the
keel ahead of the lifting strap location. This should not
be ahead of 1/3 aft of where the bow meets the waterline.
Planing Hull
On planing hulls the transducer is typically placed near
the transom. This is to provide smooth flowing water at
the greastest speed. However, most planing hull boats
create transducer aeration when on plane regardless of
transducer location.
It should be noted that thru-hull transducers can effect
boat performance in two important ways. The first
concern is cavitation created by the transducer that causes
reduced engine performance by disrupting water flow
around the propeller. This is smoothed out by the hull in
some boats, but on planing hulls with the transducer near
the transom, the hull is not able to clear the cavitation.
The second concern is uneven drag on smaller high-speed
boats. This may occur when the thru-hull transducer is
mounted far off of the centerline of the boat. At low
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