Retractable Transducer; Towed Body Installation - Simrad ES70 - INSTALLATION REV A Installation Manual

Simrad ES70

Retractable transducer

Hull units allowing the transducer to be lowered and hoisted are commonly used for
horizontal looking sonars. When not in use, the transducer is retracted into a trunk.
The retractable hull unit is more expensive than a blister, but on vessels with a hull where
it is difficult or impossible to install a blister, it may still be worth while. The principles
of a hull unit with a retractable transducer is shown below.
Vessels without a keel and with a wide, flat bottom is an example where a retractable
hull unit can be the only acceptable method for bringing the echo sounder transducer
below the boundary layer.

Towed body installation

Installation on a towed body
Transducers designed to withstand large water pressure are provided for use in towed
bodies. The recommended installation method is through the hull plating hull using
mounting and clamping rings. The installation arrangement on the towed body must be
designed by the manufacturer of the towed body to fit its shape and characteristics.
134
A Transducer
B Trunk
C Transducer
shaft
D Transducer
shaft sleeve
Keel
E
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