Humminbird 1158c Combo Installation And Operation Manual page 41

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).
Areas of Possible Turbulence
Rivets
Transom
• 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.
Strakes
15"
Find a turbulence-free location at least 15" from the propeller(s)
and not in line with trailer bunks or rollers.
Step
Hull
29
Stepped Hull
Level
Transom Mount - DualBeam™ PLUS
Rib