Question

Describe the hull examination that should be carried out on a ship in dry dock. Making special reference to essential maintenance and repairs that can only be carried out in dry dock.

Answer

A docking survey would also provide the opportunity for inspection of the hull internal on decks, as would be carried out in an Annual Survey, so that ship is examined as far as necessary and practical {i.e. as far as can be seen) to establish that the general condition and documentation is satisfactory. Condition is satisfied by inspecting:

The condition of the hull and closing appliances including: weather decks, hatchways, vents, air pipes, casings, scuttles, scuppers, rails, freeing; ports, gangways, walkways, permanent fittings, for cargo

Anchor and mooring equipment;

Watertight bulkhead penetrations;

Fire protection arrangements;

Hatch closing arrangements; ballast tank surfaces.

Main and auxiliary machinery

Emergency escape routes.

However, inspection of the underwater hull would be the main reason for the dry docking and therefore, those parts to be examined which are generally only carried out in the dry dock could be listed as follows:

Hull condition. - Corrosion/ fouling.

plate work damage - dents, cracks etc. may involve removal/replacement of plates and associated stiffening, leaks - welds gouged and re-welded, sacrificial anode condition - replace if necessary, ship side valves/cocks examined, greased, serviced. Water boxes cleaned and painted, grids checked/replaced, tanks drained, cleaned and inspected

shaft wear down readings taken. propeller blades inspected for cracks/cavitation erosion/deformation CP propeller blade mechanism and fixings stern frame inspected for corrosion/cracks rudder pintle/axle clearances, carrier wear down, bilge keel condition