Installation manual

Simrad SD570 / Base version
46
851--160117 / B
In order to find out if a high noise is caused by flow noise of the
ship’s hull or by the engine/propeller, make the
acceleration/retardation test as described below.
First, enter the noise level for 0° bearing from table 7 into the
column for STABLE SPEED in table 8.
Then, at 0 knot, give full engine thrust, and make a readout of the
noise level for ACCELERATION when reaching each of the listed
speeds. Enter the readouts into the table.
Then, at full speed, reduce the engine thrust for minimum speed,
and make the readouts for RETARDATION.
SPEED
(
K
N
O
T
S
)
BEARING 0°
(
K
N
O
T
S
)
STABLE SPEED ACCELERATION RETARDATION
0
2
4
6
8
10
12
14
Table 8 Noise verification
Make a dashed line plot of the acceleration noise into the
noise/speed table 9, and a dotted line for the retardation noise.
By comparing these three plots it should be possible to sort out if
the main noise is caused by flow noise or engine/propeller noise.
If the main noise is caused by flow noise, the ship’s hull should be
thoroughly inspected next time when docking. If the noise is
caused by the engine propeller, ensure that the propeller is not
chipped or corroded.