Humminbird 1157c Combo Installating And Operation Manual page 39

Measuring the Transom Angle
Plumb
line
12"
Transom
Angle in
degrees
(°)
Measured
Distance (X)
Transducer Knuckle Positions
Ratchets Placed in Position 2
Rib
NOTE: It is important to take your measurement in the figure showing
Measuring the Transom Angle, from exactly 12 inches down from the top of
the transom.
2. Place the two ratchets, one on either side of the transducer knuckle,
so that the beads on each ratchet line up with the desired position
number on the knuckle. If you are setting the ratchets at position 1,
the beads on each ratchet will line up with the rib on the transducer
knuckle to form one continuous line on the assembly.
NOTE: The ratchets are keyed; make sure that the square teeth on each
ratchet face the square teeth on the transducer knuckle, and the triangular
teeth face outward.
Weight
Hold the ratchets on the transducer knuckle with one hand and fit the
pivot arm over them until it snaps into place with the other hand.
Refer to the illustration.
Knuckle
Bead
Ratchet
Ratchets Placed in Position 1
Rib at
position 1
Fitting the Pivot Arm Over the Ratchet
29
Beads
Ratchet