Prerequisites
The vessel is in dry dock. The SN90 system is turned off. Neither tools nor instruments are required for the visual inspection.
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Relevant tools are required to remove marine growth and to apply anti-fouling paint. All tools must be provided by the shipyard. |
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Anti-fouling paint must be provided by the shipyard. |
NoteDo not direct high-pressure water or sandblasting spray towards the transducer. This will damage the transducer beyond repair.
Two persons are needed to do the task.
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One person must stay in the sonar room to operate the hull unit. |
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One person must stay in the dry dock, under the hull, to make sure that the transducer is not lowered too far down. |
Proper oral communication must exist between the sonar room and the dry dock personnel.
NoteA hull unit may be provided as an option. It allows you to lower and hoist the transducer. All information and tasks related to the hull unit may be disregarded and omitted if the SN90 system is installed without this unit.
Procedure
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Make sure that all power to the hull unit is disconnected. |
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Cover the opening in the installation trunk with a solid wooden or steel plate to protect the transducer. |
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Do a close visual inspection of the blister and the hull plating close to the installation trunk.
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Apply anti-fouling paint to protect the hull plating and prevent marine growth. |
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Make sure that all surfaces are protected with a high quality coating. |
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Access the inside of the installation trunk. |
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Do a close visual inspection of the inside of the installation trunk.
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Remove marine growth.
NoteDo not direct high-pressure water or sandblasting spray towards the transducer. This will damage the transducer beyond repair.
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b |
Apply anti-fouling paint. |
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Make sure that the inside of the installation trunk is properly protected with coating. |
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Use the hand crank to hoist the transducer. |
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While hoisting, make sure that you have ample space between the transducer and the inside wall of the installation trunk. |