HULL EXAMINATION IN DRY DOCK - ESSENTIAL MAINTENANCE, REPAIRS AND SURVEY OF SHIP SIDE FITTINGS
Hull examination:
- Preparation: With the vessel in dry dock, the hull is washed down and the dock is dewatered. The hull is examined externally for damage, corrosion, wastage, fouling and deformation.
- Hull plating: Examine the bottom, side and shell plating for corrosion, pitting, wastage, buckling, cracks, and damage (from grounding, collision, or impact). Measure the plate thickness (ultrasonic) where wastage is suspected.
- Welds/ seams: Examine the welded seams and riveted joints for cracks, corrosion and leakage.
- Keel/ bilge keel: Examine the keel and bilge keels for damage, corrosion and wastage.
- Frames/ stiffeners: Examine the internal frames and stiffeners (where accessible) for corrosion, cracking and damage.
- Appendages: Examine the rudder, propeller, shaft, and the sea chests/ gratings for damage, corrosion and fouling.
- Anodes/ cathodic protection: Check the sacrificial anodes and the ICCP system for condition and consumption.
Essential maintenance and repairs:
- Clean the hull (remove fouling, marine growth) and apply anti-fouling/ protective coatings.
- Repair/ renew wasted or damaged hull plating and welds.
- Renew the sacrificial anodes and service the cathodic protection.
- Repair/ renew the rudder, propeller, shaft and the sea chests as required.
- Repair any leaks/ damage found.
Survey of ship side fittings:
- The ship side fittings (sea chests, valves, gratings, overboard discharges, and the shell fittings) are surveyed:
- Sea chests and gratings: examined for corrosion, blockage and damage; cleaned and repaired.
- Overboard/ sea valves: examined for corrosion, wastage and correct operation; overhauled/ renewed as required.
- Shell fittings (e.g. the rudder stock gland, the shaft gland, the echo sounder/ log transducers): examined for condition and leakage.
- The fittings are pressure-tested/ leak-tested as required.
- The findings are recorded and the repairs are carried out to the maker's/ Class requirements, with the surveyor's approval.