Avoid Protruding Objects Near The Transducer; Mount The Transducer At Forward Part Of Hull To Minimize The Effects From The Flow Boundary Water Layer - Kongsberg Simrad CP200-5C Installation Manual

Simrad CP200-5C Installation Manual

Avoid protruding objects near the transducer

Objects protruding from the hull will generate turbulence and flow noise. This will reduce
the overall performance of your system.
Protruding objects may be zinc anodes, transducers or even the vessel's keel. Holes and pipe
outlets are also important noise sources, as well as rough surfaces caused by bad welding.
Even traces of sealing compound, sharp edges, bolts or empty bolt holes will create noise.
All these protruding objects may act as resonant cavities amplifying the flow noise at
certain frequencies.
Do not place a transducer near protruding objects, and especially not close behind them.
Make sure that the surface of the transducer face, the hull plating and putty around the
transducer is as even and smooth as possible. Mounting screws or bolts must not be
extruding from the transducer, the installation hardware or the hull plating. If necessary,
grind and polish all surfaces.
Related topics
Preparations, page 22
Where to install the transducer, page 38
Mount the transducer at forward part of hull to minimize the
effects from the flow boundary water layer
The upper water layers of the sea contain a myriad of small air bubbles created by the
breaking waves. When the hull moves through water it will cause a disturbance, and this
will generate friction. The friction zone is called the flow boundary layer.
The water flow in this boundary layer may be laminar or turbulent.
• The laminar flow is a nicely ordered, parallel movement of the water.
• The turbulent flow is a disorderly flow pattern, full of eddies.
Turbulent flow Laminar flow Air bubbles
A B C
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