Preparations before Dry-docking

1. Prepare Repair Specifications in advance for budgeting and inviting quotations
2. Pipe Lines
3. Structural steel renewal, for which plate thickness gauging may be required.
4. Overhauling of Mooring Equipment.
5. Special servicing requirements
6. Overhauling and testing of Cargo Gear ( cargo pumps if the vessel is a tanker)
7. Prepare Spare Parts
8. Plan and carry out Hold/tank cleaning/gas freeing before arrival
9. Check and confirm availability of special tools, instruments and manuals on board.
10. Confirm availability of drawings like Docking Plan, GA etc. on board.
11. Make a repair and maintenance list, create or obtain a drydock handbook if required, and assign responsible ship staff to their duties on the list. Divide staff into groups to oversee the work carried out by yard gangs.
12. All spare parts must be checked and repair items kept ready for use.
13. Previous dry dock reports should be studied and previous clearance measures noted.
14. Clean engine room tank top and bilges.
15. Prepare sewage treatment tanks, dirty oil tanks and bilge tanks.
16. Flushing of bilge lines is to be carried out prior to dry dock.
17. The oil-water separator filter element should be renewed and the system checked for satisfactory operation.
18. Minimum bunkers (Fuel Oil and Fresh water) and ballast carried.
19. All heavy weights secured prior to dry dock.
20. All tanks and cofferdams must be sounded and recorded.
21. Firefighting plans and safety measures discussed before dry dock
22. Firefighting equipment on board should be checked and kept ready for use.
23. Emergency lighting and generator should be tested before entry.
24. Escape routes must be clearly marked.
25. All valves and chests to be overhauled must be clearly marked.
26. Shore connections for cooling water and fire line are to be readied.
27. Main engine, generators, and boiler are changed over to diesel oil.
28. CO2 total flooding systems are secured and locked before entry.
29. Vessel must approach dock with even keel.

Management Involvement

• 1. Select repair yard based on vessel’s trading pattern.
  2. Invite quotations and negotiate prices.
  3. Issue instructions to Master/Chief Engineer regarding: Cargo/ballast/fuel oil quantity/distribution, Calculation of arrival drafts and trim, Fire/ Safety precautions.

Trouble/Damage if Dry Docking is Unprepared:

1. Dangerous confusion if no proper defects list is made and staff not briefed.
2. Explosion hazards when hot work is done on a tank not emptied of volatile substances.
3. Engine room bilges may become fire hazards if not cleaned.
4. If spares are not checked properly, work will be delayed due to time wasted finding or awaiting orders.
5. Leakage due to draining must be pumped to the empty drain/bilge tanks if not empty prior to dry dock.
6. Extra unplanned work needed in shore reception required in dry dock costs time and money.
7. Wrong frequency and power supply information given to dry dock will cause machinery to overheat and eventually fail.

Safety during docking

1. Firefighting equipment ready at all times.
2. Fire detectors and fire alarm in good working condition.
3. CO2 total flooding system door is locked to prevent accidental actuation.
4. Safety gear worn while working- safety shoes, helmet, overalls, safety goggles, ear mufflers, and gloves.
5. Escape routes should be clearly marked.
6. Proper working permits obtained before carrying any work on board; e.g. hot work permit, enclosed space entry permit.
7. All lifting gears checked to be in good working condition.
8. Safety lamps are used – never use a naked lamp.
9. Co-ordination of work, so no chemical cleaning and hot work around boiler area is done at the same time.
10. No transfer of oil carried out in dry dock.
11. No boiler blow downs; in emergency, necessary notice given.
12. Acetylene and oxygen bottles are properly stored and secured.
13. Fire officer at site of work and extinguishers available.
14. No unauthorized personnel or chemicals allowed on board.
15. Ship properly grounded to shore earth.
16. Fire line is always ready with 2 hydrants open if no hull work is carried out.
17. Safety meetings should be carried out every morning before stating the work in dry dock.
18. Warning notices
19. Fire line under pressure/ fire fighting appliances kept ready
20. Means of communications established
21. Usage of galley and WCs restricted as required.
22. Hot work permissions/precautions
23. Earthing of vessel
24. Escape route. Two fixed gangways, independent of each other.
25. Safety plan of the vessel available at gangways.
26. Suitable communication system and routine for alarm in emergency situations
27. Ship watch round regularly
28. Contact with fire-brigade ashore.
29. Water under pressure to the vessel’s fire-hose and sprinkler system.
30. Hot work permit
31. Fire watch at least during hot work plus two hours
32. Portable extinguishers and a connected fire-hose where hot work is performed.
33. Secondary fire alarm system where necessary
34. Debris contributing to fire load sent ashore
35. Fire-doors or WT-doors fully operational at all time
36. Gas free certificate

Inspections during Docking Survey

1. The shell plating is to be examined for excessive corrosion, deterioration due to chafing or contact with the ground and for undue unfairness or buckling.
2. Special attention is to be given to the connection between the bilge strakes and the bilge keels.
3. The clearances in the rudder bearings are to be measured. Where applicable, pressure testing of the rudder may be required if deemed necessary.
4. The sea connections and overboard discharge valves and cocks and their attachments to the hull are to be examined. 
5. The propeller, stern bush and sea connection fastenings and the gratings at the sea inlets are to be examined.
6. The clearance in the stern bush or the efficiency of the oil glands is to be ascertained.
7. When chain cables are ranged, the anchors and cables are to be examined by the Surveyor.

Activities In Dry dock

• Bottom Inspection/corrective action
• Bottom painting
• Anchor cable ranging and painting.
• Cleaning and painting of chain locker.
• Echo-sounder and speed log checks
• MGPS and ICCP checks
• Sea chests/filters cleaning/painting
• Storm valves overhauling
• Rudder pintle and jumping clearances checking
• Rudder pressure testing/internal painting if required
• Poker gauge reading (Propeller drop)
• Stern seal leak check
• Propeller polishing/repairs if required.
• Tail shaft survey, if required.
• Bottom plugs removal/re-fitting as required

Checks before/during Flooding in Dry Docking

• Sea connections, sea chests checking
• Bottom plugs fitting/leak test by vacuum
• Any other hull opening
• Removal of masking of anodes
• Securing of rudder fittings, propeller nut/cone fitting, rope guard and net-cutter fitting
• Ensuring ballast/weight distribution same as when docked
• After commencement of flooding, when the water level has risen enough to cover all shipside opening, flooding needs to be stopped and all ship side connections checked for any leakage. After confirming that all are satisfactory, flooding is resumed and the vessel floated.

quote: https://www.brighthubengineering.com/seafaring/77001-preparing-the-ship-for-dry-dock/

What is Dry Dock Survey ?

A  dry docking Survey is required in conjunction with the Special Survey to examine the external underwater part of the ship and related items.

Two Bottom surveys are required to be carried out during the five year period of validity of SOLAS Cargo Ship Safety Construction (SC) Certificate, and the maximum interval between any two successive Bottom Survey is not to exceed three years.

From 1 July 2002, for bulk carriers of 15 years of age and over, inspection of the outside of the ship’s bottom is to be carried out with the ship in dry dock. 

For bulk carriers less than 15 years of age, alternative inspections of the ship’s bottom not conducted in conjunction with the Special Survey may be carried out with the ship afloat. Inspection of the ship afloat is only to be carried out when the conditions are satisfactorily and the proper equipment and suitably qualified staff are available.