5 types of vessel repair: Annual repair, Ship Voyage repair
Annual vessel repair:
Once 1-2 years. Passenger vessels and reefer vessels may have shorter intervals, and cargo vessels and barges may have longer intervals. Annual repair is processed in the yard dock (dry dock and wet dock). Annual vessel repair is to be carried out in the dockyard (dry dock, floating dock) or on the marine railway. Annual repairs are mainly for maintenance, such as removing clinging marine organisms and repainting the hull, checking propeller and rudder, measuring tail shaft clearance, grinding submarine valve, and checking the cylinder of the main/auxiliary engines, etc. Annual repair is usually carried out with an annual survey, the surveyor will check the hull, safety equipment, survival equipment, fire fighting equipment, lifting equipment, power plants, electrical equipment, communication navigation equipment, and so on over 20 projects appear inspection. Repair every defect to sail safely until the next annual repair.
Intermediate vessel repair:
Once 4-6 years after 2-3 annual repairs. The repair scope of intermediate repair is larger than annual repair. It has preventive properties and is to be carried out in the dockyard ( dry dock, floating dock) or on the marine railway. Intermediate repair is generally combined with a special inspection. The surveyor will overhaul, measure, and test the hull, all main equipment, and over 40 projects. According to the inspection results, repair all the projects which may affect the safe navigation until the next intermediate repair to ensure the service life.
Ship Voyage repair:
before annual repair or intermediate repair, the shipyard sends workers to the ship at anchor, anchorage, or at sea to assist the crews to troubleshoot temporary faults to keep the vessel in operation.
Vessel Emergency repair:
Repairs to eliminate damages caused by collision, grounding, fire, and other Marine accidents or machine accidents. The vessel inspection institution shall examine and appraise the extent of damage and scope of repair to the vessel caused by the accident.
Modified repair:
Modification, and repair work to improve the performance of the vessel or change the purpose of the vessel. Such as lengthening the hull, changing the ordinary vessel into a special vessel, changing the power plant from a steam engine to a diesel engine, etc. The vessel inspection authority shall design and approve any alteration involving the basic structure and main parameters of the vessel.
