NorthStar Navigation 491 User Manual
Page 10

SECTION TWO — Installing the transducer
PAGE 6
491 INSTALLATION MANUAL Revision A
•
the path for running the transducer’s cable is reasonably direct—keep
in mind that the transducer cable is 33 feet long (10 meters). To pre-
vent damage, coil any excess cable and secure it
•
water turbulence and noise are minimal, decreasing the amount of
bubbles passing over the transducer face
•
the transducer isn’t behind hull irregularities or near eroding paint;
both indicate areas subject to turbulence
•
the transducer is as far as possible from the engine or propellers, and
inboard of the lifting strakes
•
the transducer always remains submerged and parallel to the water
surface
•
the transducer is easily accessible from inside the vessel for adjust-
ments and maintenance
•
the transducer’s ultrasonic beams aren’t obstructed by the keel, pro-
peller shafts, or any other part of the vessel
•
the hull thickness falls within the limits in Table 3 below (all dimen-
sions are perpendicular to the waterline):
Table 3: Hull thickness limits
Model
Minimum
Maximum
AirMar B44V/B744V with fairing
6 mm (1/4 inch)
19 mm (3/4 inch)
AirMar B44V/B744V without fairing
6 mm (1/4 inch)
65 mm (2 1/2 inches)
AirMar B260 with fairing
——
45 mm (1 3/4 inches)
AirMar B260 without fairing
19 mm (3/4 inch)
114 mm (4 1/2 inches)