Installation manual

Final tests and measurements
147
851-164574 / C
Speed
(
K
n
o
t
s
)
Bearing
(
K
nots
)
--120° -- 6 0 ° 0° +60° +120° +180°
0
2
4
6
8
10
12
14
Table 8 Noise measurements
8 When the measurements are finished, make a plot of the
noise for 0 degrees bearing into the Noise speed plot.
- The noise level at full speed should preferably not exceed
the 0 dB line.
→ Refer to the plot provided on page 149.
This noise/speed curve can give a picture of the ship’s best search
speed.
Problems with flow noise
In case of very high ship noise levels, the RCG function will
automatically regulate the receiver gain down. This lower gain will
then cause a reduction in the receiving range.
To find out if this high noise level is caused by flow noise f rom the
vessel’s hull or by the engine/propeller, perform the following test.
1 Enter the noise level for 0 degrees bearing from the Noise
measurements table into the column for Stable speed in the
Noise verification table.
→ The Noise measurement table is given as table 8 on page
147.
→ The Noise verification t able is given as table 9 .
2 From 0 knots, give full engine thrust, and make a readout of
the noise level for Acceleration when the vessel reaches
each of the listed speeds. E nter the readouts i nto the table.
3 From full speed, reduce the engine thrust for minimum
speed, and make similar readouts for Retardation.