Designing and mounting mechanical support brackets to secure the hull unit
Due to its height and weight, the hull unit gantry must be secured to the bulkhead by means of mechanical support brackets. The dimensions and strength of the support brackets must be adequate to prevent vortex induced vibrations. This is an invariable requirement to ensure the safety of the SU90 system and the vessel.
Prerequisites
The shipyard must provide all necessary tools and manpower.
Image
Illustration:
A Mechanical support brackets
B Bulkhead
C Hull Unit
Context
The forces to which the hull unit is exposed depends on its physical size, its location, and the vessel's behaviour in rough sea. It is very important that the hull unit is sufficiently supported.The forces applied by vibrations and the vessel's movements in the sea can affect the quality of the system performance, the endurance of the physical installation, and the vessel's safety.
The mechanical support brackets must be designed and manufactured by the installation shipyard to fit the complete installation in the sonar room. All calculations made to support the design must meet the applicable safety requirements, and apply to the physical properties of the complete installation.
We recommend that support brackets are placed pointing at minimum three directions with approximately 120 degrees between them.
Note
The final design and the installation must be approved by the classification society. Without a proper mechanical support for the hull unit gantry, the guarantee will be void!
It is the installation shipyard's responsibility that the installation trunk and the hull unit gantry are properly secured against vibrations and sudden movements caused by the vessel's behaviour in the sea.
Procedure
1 Locate the two holes provided on the hull unit gantry.
2 Design, manufacture and mount proper mechanical support brackets from the top of the hull unit to the bulkhead.
The dimensions and strength of the support brackets must be adequate to prevent vortex induced vibrations.
a Mount the support brackets using bolts.
b Verify that it is possible to remove the support brackets if maintenance is required.
c Verify that the transducer cable is not obstructed by the support brackets.
3 Design, manufacture and mount proper mechanical support brackets from the top of the mounting flange to the bulkhead.
a Mount the support brackets using two (or more) of the existing mounting flange bolts.
b Verify that it is possible to remove the support brackets if maintenance is required.
c Verify that the transducer cable is not obstructed by the support brackets.
4 If applicable:
a Do a close visual inspection of the physical properties of the installation trunk and the way it has been installed.
b Make sure that the installation trunk has been properly braced to the hull plating and the surrounding hull frames.
c Make sure that the installation trunk has been properly stiffened in both the fore-and-aft and athwartship directions by means of strengthening knee plates.