Marine Engineering Study Materials

Inspections during Docking Survey

• 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.
• Special attention is to be given to the connection between the bilge strakes and the bilge keels.
• The clearances in the rudder bearings are to be measured. Where applicable, pressure testing of the rudder may be required if deemed necessary.
• The sea connections and overboard discharge valves and cocks and their attachments to the hull are to be examined. 
• The propeller, stern bush and sea connection fastenings and the gratings at the sea inlets are to be examined.
• The clearance in the stern bush or the efficiency of the oil glands is to be ascertained.
• When chain cables are ranged, the anchors and cables are to be examined by the Surveyor.

Preparations before Dry-docking

• Prepare Repair Specifications in advance for budgeting and inviting quotations
• Pipe Lines
• Structural steel renewal, for which plate thickness gauging may be required.
• Overhauling of Mooring Equipment.
• Special servicing requirements
• Overhauling and testing of Cargo Gear ( cargo pumps if the vessel is a tanker)
• Prepare Spare Parts
• Plan and carry out Hold/tank cleaning/gas freeing before arrival
• Check and confirm availability of special tools, instruments and manuals on board.
• Confirm availability of drawings like Docking Plan, GA etc. on board.

Management Involvement

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

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

Safety in Dry Docking

• Warning notices
• Fire line under pressure/ fire fighting appliances kept ready
• Means of communications established
• Usage of galley and WCs restricted as required.
• Hot work permissions/precautions
• Earthing of vessel

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.