One of the vessel from Singapore based Ship Management Company, had misplacement of rudder stock /rudder from its original position.
Following deviations were observed in the rudder position , while executing command from bridge room.
COMMAND IN BRIDGE ROOM
|1||PORT SIDE||No Movement|
|2||MID SHIP||STBD – 30 deg|
|3||STBD – 30 deg||STBD > 30 deg|
DEFECT ORIGIN :
Key position of the rudder found to have slipped away from its position on the stock and got stuck up in the STBD position.
REPAIRS CARRIED OUT SUCCESSFULLY IN RECORD TIME :
- Erected hanging scaffolding to access the rudder from Aft peak.
- Detachable plates were cropped & removed in way of rudder stock nut on the rudder.
- Weld area of Nut lock plate found sheared off while the rudder was turned down from the stock towards clockwise.
- To rectify and reposition the rudder , we tried to loosen, but found it got jammed with the rudder.
- We secured the Rudder with 4 chain blocks.
- Tiller appendages were marked and disconnected from the position.
- Reference marks were made and measurements were recorded.
- Tiller nut on the rudder stock was dismantled.
- Tiller pressurized up to 1100 Bar to push up and got released.
- Hydraulic systems were isolated and tiller was secured using chain blocks and tried out for free movement from the stock and found it moving free.
- Rudder turned to zero position and secured with chain blocks in-situ.
- After alignment of rudder position to zero , tiller aligned to 00 & dropped down.
- Pressurized up to 1100 Bar to push down and lock nut tightened.
- All appendages were fitted back to its original position.
- Rudder inspection covers were fitted back and welded.
- DPT carried out in way of welding.
- De-erected hanging scaffolding & operation tests were carried out and found to be satisfactory.
- UW inspection also carried out in the mean while in way of rudder pintle, propeller, horn areas & sea chests.
- Service team sailed along with the vessel till outer anchorage to conduct sea trials and found to be satisfactory.