Humminbird 1157C Fish Finder User Manual


 
1. Locating the transducer mounting location
NOTE: If transom mounting is not possible because of a stepped hull or cavitation noise, and you have a
single layer fiberglass hull, In-hull installation is an option. See Inside the Hull Transducer Installation for
more information.
Turbulence: You must first determine the best location on the transom to install the transducer. It is very
important to locate the transducer in an area that is relatively free of turbulent water. Consider the
following to find the best location with the least amount of turbulence:
As the boat moves through the water, turbulence is generated by the weight of the boat and the
thrust of the propeller(s) - either clockwise or counter-clockwise. This turbulent water is normally
confined to areas immediately aft of ribs, strakes or rows of rivets on the bottom of the boat, and in
the immediate area of the propeller(s). Clockwise propellers create more turbulence on the port side.
On outboard or inboard/outboard boats, it is best to locate the transducer at least 15" to the side
of the propeller(s).
The best way to locate turbulence-free water is to view the transom while the boat is moving. This
method is recommended if maximum high-speed operation is a high priority. If this is not possible,
select a location on the transom where the hull forward of this location is smooth, flat and free of
protrusions or ribs.
15”
Find a turbulence-free location at least 15" from the propeller(s)
and not in line with trailer bunks or rollers.
Level
Areas of Possible Turbulence
Rivets Strakes
Transom Hull
Stepped Hull
Step Rib
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