Lowrance Skimmer Transducer Installation Instructions Manual page 4

slightly higher or lower. (The slots in the mounting brackets allow you
to loosen the screws and slide the transducer up or down.) If you fre-
quently lose bottom signal lock while running at high speed, the trans-
ducer may be coming out of the water as you cross waves or wakes.
Move the transducer a little lower to help prevent this.
If you cruise or fish around lots of structure and cover, your transducer
may be frequently kicking up from object strikes. If you wish, you may
move the transducer a little higher for more protection.
There are two extremes you should avoid. Never let the edge of the
mounting bracket extend below the bottom of the hull. Never let the
bottom – the face – of the transducer rise above the bottom of the hull.
Shoot-thru-hull vs. Transom Mounting
In a shoot-thru-hull installation, the transducer is bonded to the inside
of the hull with epoxy. The sonar "ping" signal actually passes through
the hull and into the water. This differs from a bolt-thru-hull installa-
tion (often called simply "thru-hull"). In that case, a hole is cut in the
hull and a specially designed transducer is mounted through the hull
with a threaded shaft and nut. This puts the transducer in direct contact
with the water.
Typically, shoot-thru-hull installations give excellent high speed opera-
tion and good to excellent depth capability. There is no possibility of
transducer damage from floating objects, as there is with a transom-
mounted transducer. A transducer mounted inside the hull can't be
knocked off when docking or loading on a trailer.
However, the shoot-thru-hull installation does have its drawbacks.
First, some loss of sensitivity does occur, even on the best hulls. This
varies from hull to hull, even from different installations on the same
hull. This is caused by differences in hull lay-up and construction.
Second, the transducer angle cannot be adjusted for the best fish arches
on your sonar display. (This is not an issue for flasher-style sonars.)
Lack of angle adjustment can be particularly troublesome on hulls that
sit with the bow high when at rest or at slow trolling speeds.
Third, a transducer CAN NOT shoot through wood and metal hulls.
Those hulls require either a transom mount or a thru-hull installation.
Fourth, if your Skimmer transducer has a built in temp sensor, it will
only show the temperature of the bilge, not the water surface temp.
Follow the testing procedures listed in the shoot-thru-hull installation
section at the end of this instruction booklet to determine if you can
satisfactorily shoot through the hull.
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