Kongsberg SBP 29, Installation Manual

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Keep the SBP 29 far away from the propellers
The propulsion propellers is the dominant noise source on most vessels. The noise
is easily transmitted through the water. This noise may often reduce the overall
performance of your SBP 29.
The SBP 29 must be installed as far away from the propellers as possible. The best
positions are therefore on the fore part of the hull. Positions outside the direct line of
sight from the propellers are best.
On small vessels we recommend mounting the SBP 29 on that side of the keel where the
propeller blades move
upwards . This is because the propeller cavitation is weakest on
that side. The cavitation starts when the water flows in the same direction as the propeller
blades. This is where the propeller blades move downwards.
Mount the transducer at a safe distance from bow thruster(s)
Bow thruster propellers are extremely noisy. When you decide where to place the
SBP 29, you must consider the noise created by most bow thrusters.
When in operation, the noise and cavitation bubbles created by the thruster may make
your SBP 29 Sub-bottom profiler useless, almost no matter where the SBP 29 is installed.
When the bow thrusters are
not in operation, the tunnel creates turbulence. If your vessel
is pitching, the tunnel may be filled with air or aerated water in the upper position and
release this in the lower position.
In general, the SBP 29 should therefore be placed well away from the bow thruster(s).
However, this is not an invariable rule. Certain thruster designs - combined with their
physical locations on the hull - may still offer a suitable location for the SBP 29, even
close to the thruster. If you are in doubt, consult a naval architect.
Summary and general recommendations
Some of the installation guidelines provided for SBP 29 location may be conflicting. For
this reason, each vessel must be treated individually in order to find the best compromise.
In general, the most important factor is to avoid air bubbles in front of the SBP 29 face.
For this reason, the recommended SBP 29 location is normally in the fore part of the
hull, well ahead of the noise created by the bow wave.
The maximum distance from the bow is normally equal to one third of the total water
line length of the hull.
Note
Mounting the transducer more than 10–15 meters from the bow may cause problems
with the turbulent flow.
Preparations