Installing the mounting flange
The mounting flange must be mounted so that its top mating surface is in parallel with the sea surface during normal operating conditions. The transducer dock on top of the gate valve must remain vertical during the same conditions.
Prerequisites
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This task must take place in dry dock. The shipyard must provide all necessary tools and manpower. The following specific items are required for this task.
•  Lifting arrangement
•  Welding equipment
Note
The mounting flange is heavy. Always use appropriate lifting equipment to minimize risk of personnel injury or equipment damages. Only certified equipment must be used.
Context
Only the basic steps of the task are offered. Additional procedures with more information and/or details must be provided by the installation shipyard to fit the vessel properties.
The top mating surface of the mounting flange must be protected with a wooden cover at all times until the gate valve is installed. It is very important that this surface is clean and undamaged, because it must be watertight after the gate valve has been installed.
Note
The quality of the welding is critical to the safety of the vessel. Welding must only be done by a certified welder. Always wear the personal protective equipment. Observe and obey the relevant safety instructions.
The final installation work must be approved by the vessel’s national registry, the corresponding maritime authority and/or classification society.
Procedure
1 Define the physical location of the mounting flange.
This location must be carefully selected. The decision must be based on the general principles outlined in chapter Preparations and all relevant knowledge about the vessel construction.
Note
All information related to practical and theoretical noise patterns along the hull must be taken into consideration.
2 Adapt the mounting flange to fit the hull.
Alternatively, design and manufacture a custom mounting flange.
Note
Keep the height of the mounting flange as small as possible, as this will increase the operational depth of the transducer.
3 Cut out a hole in the vessel’s hull with a diameter large enough to accommodate the mounting flange.
The exact size of the hole must be determined by the installation shipyard.
4 Orientate the mounting flange correctly, and weld it into position.
Note
The mounting flange must be mounted so that its top mating surface is in parallel with the sea surface during normal operating conditions.
5 Check the upper surface of the mounting flange to ensure that it is level, undamaged and clean.
6 Cover the upper surface of the mounting flange with a wooden plate to protect it
7 Add support frames and stiffeners to secure the construction.
8 Depending on the shape of the hull, we recommend that you fit a steel blister for protection.
The blister must be designed by the installation shipyard. It must be welded to the shell plating. The blister may be an open type, or it can be filled with oil to prevent corrosion. This last method provides excellent protection, and simplifies maintenance.
Note
Make sure that the hull plating surrounding the mounting flange is even and smooth without protruding objects that can cause noise. Objects protruding from the hull will generate turbulence and flow noise. This will reduce the CS90 performance. If necessary, grind and polish all surfaces.
9 As soon as all installation, welding and grinding has been done, prime or paint the mounting flange and the surrounding area using a high quality protective coating.
10 Verify that the mounting flange has been installed correctly.
a Inspect the mounting flange.
b Inspect the installation of the mounting flange, the blister, hull plating and all surfaces thoroughly.
c Make sure that the mating surface is clean and undamaged, and well protected until the gate valve is mounted.
d Check that the offsets are within tolerance