Installation trunk description
An installation trunk is required for hull unit installation. The installation trunk is not included in the standard delivery.
The installation trunk provides the physical foundation for the entire hull unit. The installation trunk penetrates the hull. The installation trunk is therefore a crucial part of the hull unit assembly. In order to ensure proper operation of the SU90 system, the physical location of the installation trunk must be carefully selected.
The installation trunk - with a blind flange - can be ordered from Kongsberg Maritime as an optional delivery. As an alternative, the installation trunk can be manufactured by the shipyard based on the drawings in this manual. A locally manufactured installation trunk can be adjusted to better fit the properties of the vessel’s hull.
Note
If the installation trunk is manufactured locally, the installation shipyard is responsible for obtaining the approval certificates from the relevant national registry.
The installation trunk is not used when a gate valve is mounted. The installation trunk is then replaced with a transducer dock.
Important
The installation trunk must be secured to the bulkheads and/or the hull by means of strengthening plates (stiffereners). The dimensions and strength of the plates must be adequate to prevent any vibrations. This is an invariable requirement to ensure the safety of the SU90 system and the vessel.
The shape and locations of the strengthening plates must be determined by the installation shipyard based on the physical properties of the installation trunk, the hull and the space available. Minimum four strengthening plates must be used. Each strengthening plate must extend all the way from the bottom to the top of the installation trunk. Only leave a small gap to allow access to the bolts and nuts used to secure the mounting flange. The minimum plate thickness is 10 mm, but the classification society can specify other dimensions.