Humminbird 1157C - Manual (Page 30)

• 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.
• The hydrodynamic shape of your transducer allows it to point straight down without deadrise
adjustment.
• On boats with stepped hulls, it may be possible to mount the trans ducer on the step. Do not
mount the transducer on the transom behind a step to avoid popping the transducer out of the
water at higher speeds; the transducer must remain in the water for the control head to
maintain the sonar signal.
• If the transom is behind the propeller(s), it may be impossible to find an area clear from
turbulence, and a different mounting technique or transducer type should be considered (see
Trolling Motor Transducer Installation).
• The Side Imaging transducer must NOT have anything obstructing the ‘view’ of the side looking
beams, i.e. nothing can be in the line of sight of these beams (not a hull, motor, or other
transducer, etc).
To mount the transducer bracket to the boat:
1. Remove the transducer mounting template from this manual. See Appendix A for the Transducer
Mounting Template.
2. Hold the template on the transom of the boat in the location where the transducer will be
installed. Align the template vertically, matching the lower edge of the transom with the bottom
corner of the template. If your propeller moves clockwise as the boat moves forward, mount the
transducer on the starboard side, and use the bottom left corner of the template. If your propeller
moves counter-clockwise as the boat moves forward, mount the transducer on the port side, and
use the bottom right corner of the template.
3. Using a pencil or punch, mark the three mounting holes on the transom. Do not mark or drill any
other holes at this time.
Level
15” (380 mm) from prop(s)
20