Kongsberg Simrad EK80, Installation Manual

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Keep the transducer 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 EK80.
The transducer 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 transducer 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.
Related topics
Where to install the transducer, page 48
Preparations, page 43
Mount the transducer at a safe distance from bow thruster(s)
Bow thruster propellers are extremely noisy. When you decide where to place the
transducer, 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 EK80 Wide band scientific echo sounder useless, almost no matter where the
transducer 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 transducer 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 transducer, even
close to the thruster. If you are in doubt, consult a naval architect.
Related topics
Where to install the transducer, page 48
Preparations, page 43
Preparations