Vessel Dry docking is one of the major concept in maritime industry of each vessel for owner/ship manager and classification society and will be perform twice in every 5 years.
Vessel dry docking, it becomes important to carry out repairs in the underwater area of the hull.
Vessel dry docking and vessel prepare for dry dock is process to be start from last dry dock to next dry dock.
Vessel dry dock process within 6 months close to next dry dock is critical time for owner and manager.
Dry dock activity
1- Repairs hull
2- Renewal of the sacrificial anodes
3-Rmove and refit of the propellers
4-Overhauling of the propulsion shafts
5--change the seals
6- Inspection and calibration of stern tube bush
7-Repair of rudders
8-Underwater hull blasting to remove fouling
9- UT gauging
10-Under water hull steel work
11- Hull painting
12- Sea chest box treatment
13- Overboard valve
14- Machineries repair
Such repair, the underwater area needs to be made proper accessible, which is the purpose served by a dry dock. It has also become a common practice in shipyards to build their ships on dry docks or repair of vessel
For such procedures, the docking plans need to be prepared taking into consideration the increase in weight of the ship structure along the building time. Once the ship has been built, the dry dock is flooded and the ship is undocked. The calculations for undocking also play a major role in the process because it is during undocking that the ship is at a risk of capsizing.
Dry docking concept is including as follow
1-Technical or preparation of vessel for dry dock
2- Operation
3- Financial /Budget
4- Safety
1-Technical
Technical concept for dry docking is including
1-Docking package or prepare maintenance list
2-send the package to yard and receive the Proper quotation
3- Purchasing the spare
4- Purchase of paint
5- Purchase the anode
6- Purchase of consumable
4-Technical condition of vessel
5- Age of vessel.
6- SS dry dock and Intermediate DD
7-Engine room tank top cleaning
Initially we will inspect vessel then will prepare dry dock package with considering of the dry dock is SS or intermediate dock.
Package will send to yard which is close to commercial plan of vessel and cost of repair will consider.
Normally in east Asia repair cost is cheaper than of other area around world.
As per dry dock repair package and location of docking indent/Request to be raise and procurement department to be proceed for purchasing of Genuine parts.
2-Operation
2-1 docking plan
2-2 Stability of vessel
DRY DOCKING operation become important matter due to vessel stability and docking plan.
Stability of vessel is very important matter from building, loading, discharge, docking and undocking therefore ship yard will prepare stability booklet for each during life time of vessel stability become important matter and metacentric height which to be positive.
Therefore, one of the prepared plan during vessel construction is docking plan which will be use entire of life.
Before vessel proceed to dry dock master /chief officer to be calculate Vessel stability when vessel to be sit in blocks by trim by aft.
3-Dry docking financial /Budget: Budget is most important concept for owner. Ship manager to be prepare financial plan and budget 6 months before dry dock with considering of vessel condition.
Budget for dry dock to be consider cost of spare, paint, anode, consumable, dry dock cost, duration of dry docking. Salary of crew, crew activity onboard during dry dock, fuel consumption during dry dock, provision for crew, work shop assistance, Special surveyor or intermediate dry dock.
With considering above factors budget will find with 10 percent deviation.
4-Safety: To prevent and eliminate any accident, incident, damage to vessel, crew or shipyard and environments HSE briefing for crew to be conducted before arrival of vessel to dry dock to be perform.
During vessel alongside to dry dock also dry dock HSE department to be perform safety meeting onboard to increase level of safety and familrization of ship staff with rule and regulation.
Before any operation /action /maintenance in dry dock risk assessment will be consider and related forms to be fill.
Regular and daily safety meeting highly recommended along with safety tour onboard by dry dock safety officer and vessel safety officer time to time.
The major accident during dry dock could be categorized as follow:
4-1 FIRE: during dry dock the most of accident happened due to hot work to adjacent of painting or chemical store, hot work in adjacent of fuel tank or sludge tanks, hot work adjacent of bulkhead have flammable material, hot work adjacent to flammable material same as rope, hot work in engine room, fire due to short circuit in electrical cable.
4-2 Oil spill: normally vessel will arrive to dry dock by the minimum amount of fuel to prevent oil spill during of transferring of fuel if required
Oil spill may could be cause by transferring of sludge or bilge water to shore facility.
4-3 Person injury or personal death: during dry dock there is potential of personal injury therefore safety gear for crew to be monitor by ship safety officer for proper wear including safety shoes, safety helmet, coverall,
During dry dock the Other sources of person injury to be eliminate with proper action and plan including entry enclosed space, or arrest the sky light, lifting heavy equipment by crew without right procedure and equipment same as crane or chain block, injury by steam or hot fuel, injury by high pressure tools same as HYD jack, electrical shock due to improper insulated of cable and connection,
4-4 Damage to vessel or dock: Due to any action which without risk assessment and risk evaluation will be cause damage to vessel dock.
4-5 Damage to vessel due to Lifting equipment which use by dry dock or vessel, any lifting to be proceed as per procedure, rule and regulation.
For Lifting equipment’s continuous monitoring and maintenance to be carried out and also by firm and approve 3rd party.
4-6 Monitoring weather forecast: Weather forecast will affect to all activity during dry dock including painting, maintenance lifting of equipment’s,
4-7 Flooding of engine room: Engine room flooding is serious risk is onboard vessel during dry dock. This will cause by cooling pipe during dry berth or un safe ballasting during vessel
