Plan your Dry Dock to save time and avoid damage
Like all things Maritime, preparation is everything and it can mean the difference between life and death. The old adage of failure to prepare is preparing you to fail, can never be more true than when at sea, and in this instance, even when not.
Lack of planning when Dry Docking can lead to events which can cause serious damage. For example, engine room bilges may become fire hazards if not cleaned.
Prior to docking any vessel, adequate preparations should be made by comprehensive advance communications. Timing schedules to avoid docking with cargo on board or avoiding the use of a ‘lay-by berth’ cannot only be cost-effective but achieve safer conditions aboard the vessel to bedocked. The process of taking ships into dry docks, whether they are floating docks, graving docks, synchro-lift, hydro-lift or docking to a basic slipway,can be a complex and demanding task for those persons responsible for the operation. The ship’s crew, and especially the Chief Officer, being the ship’s working manager, will take on a great deal of responsibility in achieving a safe and successful completion of any docking period.
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As a general rule for docking a vessel, follow these best practices
1. Ships Documentation Required for Dry Docking
• The dry dock plan.
• The general arrangement plan.
• The shell expansion plan.
• The ship’s fire-fighting facility plan.
• The tanking arrangement and distribution of commodities.
• The plug plan.(This may be incorporated into the dry dock plan.)
• The Chief Officer’s repair list.
• The ship’s stability information.
• The ship’s general particulars.
• Gas free certificate (tanker vessels).
• Cargo plan and manifest if docking with cargo onboard.
• Rigging plan (cargo vessels).
• Relevant certificates, subject to effecting surveywork.
2. Vessel Preparation - Prior to entry in Dock
• Sound round all internal tank soundings (wet soundings) before entering the dry dock.
• Communicate with the dry dock manager regarding the vessel’s draught and trim to suit the dock construction.
• Prepare all necessary documentation which may berequired to complete the docking operation and the expected workload inside thedock.
• Calculate that the ship has adequate positive stability to withstand the expected ‘P’ force that will affect the vessel whentaking the blocks. The GM should be large enough to compensate for a virtualrise in ‘G’ once the keel touches the blocks and the vessel enters the critical period.
• To enhance the positive stability, all slack tanks and subsequent free surface effects should be either ‘pressed up’ or alternatively pumped out if possible. (Clearly the state of fuel oil tanks and similar commodity tanks may prove impractical to change status.)
• Any repair list should be completed and kept readily on hand, to pass over to the dry dock authorities.
• All utilities required should be ordered in ampletime to be supplied to the ship on docking.
• All storerooms, toilets and ship’s compartments should be locked for the purpose of security and any loose gear should be stowed away before entering the dock.
• Rig fenders around the vessel before entry into the dock.
• Plug and secure all upper deck scuppers to reduce the risk of pollution.
•Gas free fuel tanks that have planned work.
• Yard safety and regulation briefing.
3. In Dry Dock
Essential services that the ship would require for a period in dry dock would probably include:
• Electrical power, via shoreside generators.
• Bonding, earth wire fitting.
• Access gangways from the ship to shore.
• Garbage collection and disposal facility.
• Night watchman fire/safety and gangway security.
• Communications – land line direct to emergency services.
• Connection of water pressure availability on the fire line.
• Fresh water supply as and when own ship’s tanks canno longer supply.
• Airline connection if required for operating pneumatic tools.
• Sea circulating connection for machinery space.
5. Tests and Checks Departing Dry Dock
General tests and checks after a successful dry dockwould include the following:
• Anchor trials (where a new windlass is fitted) would be conducted in shallow water and would see both anchors dropped clear, and the full extent of the cables paid out.
• Speed trials would be conducted over a known distance with a series of timed runs. (Such activity is usually scheduled clearof other traffic and obstructions.)
• Stopping distances under normal operating conditions.
• Stopping distances when under emergency maneuvers.
• Turning circles of the vessel would also be assessed at various speeds.
• Rudder movements and helm indicators would be compared against the actual desired values.
• Emergency steering systems would be checked.
• Fuel consumption figures would normally be conducted over a known distance.
• Navigational instrument tests conducted on all relevant equipment.
• Emergency shut-down systems would be tested in open water conditions.
The need for safer ships and cleaner seas has neve been greater than it is today. The need to maintain high standards in all aspects of trade is paramount. With that in mind, Shipnet constantly develops solutions helping to keep our seas and trade alive with high standards. The Shipnet Dry Docking product provides the ship owners and ship managers a platform to plan and execute their vessels dry dock in a hassle-free manner.
REFERENCES-
Dry Docking and Shipboard Maintenance - A Guide for Industry - D.J. House
To find out more about Dry Docking and the time saving solution to help you complete your projects, take a look at Shipnet’s solution, design by mariners, for mariners.
Anil Bhardwaj
Product Consultant
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