Transducer Installation Principles; Using A Streamlined Blister - Simrad ME70 Installation Manual

Installing the transducer

Transducer installation principles

The physical installation of the ME70 transducer is basically made in the same way as for
normal echo sounder transducers. We strongly recommend that the transducer is installed
in a drop keel. Due to the functionality and scientific results required by the ME70, the
transducer installation must be done with a high degree of accuracy.
The ME70 transducer is designed to be mounted inside a keel box or a streamlined blister
under the vessel's hull. It can also be mounted using a suitable hole in the hull plating.
If your vessel is fitted with a drop keel, this is a superior platform for the ME70 transducer.
Drop keels are often used on larger research vessels. A drop keel will frequently protrude as
far as three meters below the hull. At that depth, the water is free of air bubbles up, even
during very high sea states. The vessel is then able to do reliable acoustic measurements in
open sea a larger part of the year. At the bottom of the drop keel, the ME70 can be installed
with the transducer face flushed with the horizontal plating.
Note
Observe the installation principles.
Installation principles, page 50
Topics
Using a streamlined blister, page 79
Using a drop keel, page 81
Using a steel conduit to protect the transducer cables, page 81
Inclination angle, page 83
Cable protection in drop keels, page 83

Using a streamlined blister

For vessels travelling at high speeds, a blister installation is the recommended method. The
blister will in many cases lower the transducers below the boundary layer. It will also
prevent objects in the water from damaging the transducers face.
The blister must be designed to fit each individual ship. The quality of the materials used,
as well as the quality of the workmanship must be defined by the vessel owner and the
installation shipyard. If applicable, the design and installation of the blister must be
approved by the appropriate classification society.
The best performance is obtained with a blister height of 50 cm or more. A streamlined
shape and rounded edges reduce the flow noise. A vertical leading edge or front will guide
79
345737/C