Prerequisites
The vessel is in dry dock. The SY50 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. |
The following specific tools are required for this task:
Spare part:
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Bearing block (Part number: 440749) |
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.
Procedure
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1 |
Make sure that all power to the hull unit is disconnected. |
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2 |
Cover the opening in the installation trunk with a solid wooden or steel plate to protect the transducer. |
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3 |
Do a close visual inspection of the blister and the hull plating close to the installation trunk.
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b |
Apply anti-fouling paint to protect the hull plating and prevent marine growth. |
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c |
Make sure that all surfaces are protected with a high quality coating. |
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4 |
Access the inside of the installation trunk. |
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5 |
Remove the trunk bearing.
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E |
Transducer lowered to 400 millimetres: 50 mm Transducer lowered to 600 millimetres: 250 mm
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a |
Remove one of the bolts that secure the trunk bearing to the transducer shaft, loosen the other bolt. |
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b |
Remove the trunk bearing. |
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c |
Inspect the bearing blocks. |
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d |
Replace bearing blocks that are worn or damaged. |
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6 |
Do a close visual inspection of the inside of the installation trunk.
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a |
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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c |
Make sure that the inside of the installation trunk is properly protected with coating. |
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7 |
Mount the trunk bearing onto the transducer shaft.
To place the trunk bearing at the correct height on the transducer shaft, measure the distance from the top of the transducer
flange to the bottom of the trunk bearing. See the illustration: (E)
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Transducer lowered to 400 millimetres: 50 mm |
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Transducer lowered to 600 millimetres: 250 mm |
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a |
Turn the direction of the trunk bearing so that one of the bearing blocks is aligned to the forward mark on the transducer
flange.
This is important to prevent physical vibrations. You must align one of the bearing blocks to the forward mark on the transducer flange. Later, when you fasten the transducer shaft to the gantry, rotate the shaft so that the both the forward mark and the bearing
block point directly forward.
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b |
Secure the trunk bearing to the shaft with the two bolts inside the bearing.
See the illustration: (D)
Use the following torque: 24 Nm
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c |
Tighten the bolts on the bearing blocks temporarily to allow the transducer shaft to be centred in the installation trunk. |
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d |
Move the transducer shaft carefully up and down inside the installation trunk. |
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e |
Make sure that the gap between the bearing blocks and the inside wall of the installation trunk is less than 0.5 mm.
It is important to adjust the gap between the bearing blocks and the trunk wall to reduce the friction. At the same time, the gap must not permit any vibrations when the transducer is lowered and the vessel is moving.
Make sure that the transducer shaft is placed as close to the centre of the installation trunk as possible.
Make sure that the transducer flange does not touch the installation trunk walls when you move transducer shaft.
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f |
Tighten the bolts when you are satisfied.
See the illustration: (A)
Use the following torque: 44 Nm
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8 |
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. |