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The Undocking Procedure

When the docking work is near completion, the ships personnel as well as the shipyard personnel will need to carry out their respective checks on the vessel and around the dock area. Once the ship has finished dry docking it may not be immediately ready for normal trading. There are many tests which must be carried out first. These tests engine tests and sea trials and will be explained further in this section. The dry dock is not the loading port of the ship and hence the ship would leave the dock in the ballast condition on route to its loading port.

There are various duties and logs that need to be taken before and when the ship is leaving the dock. These are summarized in the topics descussed below:

Duties of the Chief Officer prior undocking

The Undocking Process

 

Duties of the Chief Officer prior undocking

Ensure all the listed work is completed to a satisfactory standard. In particular that all 'survey work' is completed, prior to leaving the dock. To this end a final internal inspection of the vessel would be the order of the day.

Carry out an external inspection of the hull and enter the Dry Dock. This final visit to the dock floor would also encompass the replacing of any tank plugs that have been drawn. This task should not be deligated to a junior officer as the Chief Officer must sight all the tank plugs being replaced.

The Dry Dock Manager would accompany the ship's Chief Officer on final inspections and ensure that no vehicles, materials or personnel are remaining in the dock, prior to commencing any flooding operation.

Inform the ship's Master of the expected departure time and the crew would be engaged in activities to make the vessel ready for sailing. These activities would include odering the Navigator to plan the ships movement from the dock, posting the sailing board and cancelling shore leave, placing the engine room and respective personnel on standby, carrying out checks on all navigation equipment and making relevant entries into the deck and offical log books.

Ensure that a full set of tank soundings have been taken and that adequate supplies of fresh water, fuel and lubricating oil are on board to suit the ships movement needs. These tank quantities would then be applied to a complete stability check to ensure that the vessel has an acceptable GM once she floats clear of the keel blocks. Stability checks are the sole responsibility of the ships personnel and comparison should be made between the entry soundings when the vessel was last afloat.

All hatch covers would be closed up and the watertight integrity of the uppermost deck assured. Anchors and cables would be heaved up and stowed correctly aboard the vessel. All pipelines, power lines etc. would need to be disconnected and relavent manpower should be made available both ashore and aboard the ship in order to release these safely and at the appropriate time.

Tugs, the marine pilot and linesmen would need to be ordered to standby for the time of departure. Ships crew would be placed on standby on the fore and aft ends to tend moorings.

Finally, the chief officer would sign the Authority to Flood Certificate. This is provided that he is satisfied that the Dry Dock Authority has completed the docking specification and that the ship is in a seaworthy condition. This certificate should then be completed to allow the flooding of the dock to commence.

 

The Undocking Process

Before water is pumped into the dock, there are a few checks that must be made. Bottom plugs must be closed and sea chests should be in full working condition. Also, ballasting of the ship must be done. This is to ensure that the ship does not have an even keel draught (the aft draught is usually greater than the forward draught).

The pump room, which is usually located at the forward end of the dock controls the amount of water being pumped out of the dock. This is also referred to as ballasting the dock.

The gangway is lifted sometimes by means of a crane once the dock personnel have cleared the ship. Fire hydrants and all shore connections are disconnected.

The forward and aft ends of the ship are attached to shore based mooring lines which are winch controlled. A crane lifts these lines and places them on the deck so that they can be attached. These help to control the movement of the ship as it leaves the dock so as to ensure it leaves smoothly.

When the level of seawater in the dry dock reaches the sea level, the dock gates are opened.

A tug boat attaches a tug line to the aft end of the ship and begins to pull the ship backwards (out of the dock). The shore based mooring lines help to guide the ship smoothly out of the dock. Another two tugboats are on standby on either side of the ship.

Once the ship is halfway out of the dock, the aft shore based mooring lines are disconnected and the standby two tugboats attach themselves to the ship by means of tug lines.

When the ship has cleared the dock gates, the front shore based mooring lines are detached and the tug boats turn the ship around.

Once the ship is some distance away from the dry dock, the tug lines from all three tug boats are detached and the tug boats move away from the ship. The propeller is then started and ship moves away on its own propulsion.

 

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