Kongsberg EM 2040 MKII, Installation Manual

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Blister
A recommended method for transducer installation is by using a blister.
A blister is a mounting construction fully welded to the hull of the ship. The blister
contains casings, which form the main part of the unit, housing the transducer frames
and modules. The design of the blister is aimed at guiding the aerated water and air
bubbles around both sides of the installation and create an environment around the
transducer free of air bubbles.
Blisters of different sizes and shapes have been used from the early days of echo sounder
installation, and this method of installation is a well known principle. A blister is well
suited for refitting a vessel with an EM 2040 MKII system.
The blister can also be used for other sonar and echo sounder transducers.
The interior of the blister must be filled with water. Use drainage holes in the bottom and
an air outlet on the top.
The transducers must be installed flush with the surrounding surface area to ensure
best possible performance of the system.
Note
The inside surface of the blister must be protected with appropriate protective paint and
an adequate amount of sacrificial anodes.
The installation shipyard must provide all necessary installation drawings.
If required, all drawings and documents must be approved by the vessel’s national
registry and corresponding maritime authority and/or classification society.
Such approval must be obtained before the installation can begin. The shipowner
and shipyard doing the installation are responsible for obtaining and paying for such
approval.
Preparing the installation