Gate valve installation overview
To protect and enable inspection and maintenance of the transducer, a gate valve is added to the hull unit installation. By means of a mechanical construction it shuts off the bottom of the installation trunk when the SU90 system is not used.
Prerequisites
This task must take place in dry dock. The shipyard must provide all necessary tools and manpower. Appropriate lifting equipment (lifting tackle, portable crane or ship’s crane) is required. Free access through the hull or the decks must be provided.
Note
The gate valve is heavy. Appropriate lifting equipment (lifting tackle, portable crane or ship’s crane) is required. 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. For more information, refer to the other descriptions and tasks in this chapter.
Note
It is very important that the gate valve mechanisms is interfaced with the hull unit controller. When the gate valve is closed, it must not be possible to lower the transducer. When the transducer is lowered, it must not be possible to close the gate valve.
The installation trunk is not used when a gate valve is mounted. The installation trunk is then replaced with a transducer dock.
Procedure
1 Define the physical location of the mounting flange.
2 Cut out a hole in the vessel’s hull with a diameter large enough to accommodate the mounting flange.
3 Orientate the mounting flange correctly, and weld it into position.
4 Install the gate valve on top of the mounting flange.
5 Install the transducer dock on top of the gate valve.
6 Depending on mechanical support provided by the existing decks and/or bulkheads, design, manufacture an install additional mechanical support for the transducer dock.
7 If relevant, install the hydraulic system.
8 Do a close visual inspection of the mounting flange, gate valve and transducer dock to verify the quality of the installation work.