The Special (or Renewal) Surveys of the hull structure are carried out at five-year intervals for the purpose of establishing the condition of the structure to confirm that the structural integrity is satisfactory in accordance with the Classification Requirements, and will remain fit for its intended purpose for another five-year period, subject to proper maintenance and operation of the ship and to periodical surveys carried out at the due dates.
The Special Survey concentrates on close-up examination in association with thickness determination and is aimed at detecting fractures, buckling, substantial corrosion and other types of structural deterioration.
Thickness measurements are to be carried out upon agreement with the Classification Society concerned in conjunction with the Special Survey.
The Special Survey may be commenced at the 4th Annual Survey and be progressed with a view to completion by the 5th anniversary date.
Deteriorated protective coating in salt water ballast spaces and structural areas showing substantial corrosion and/or considered by the surveyor to be prone to rapid wastage will be recorded for particular attention during the following survey cycle, if not repaired at the survey.
You may also know about In water survey :
The In-water Survey is to provide the information normally obtained from a docking survey, so far as practicable. Proposals for In-water Surveys are to be submitted in advance of the survey so that satisfactory arrangements can be agreed with the Classification Society.
The In-water Survey is to be carried out with the ship at light draught in sheltered water; the in water visibility is to be good and the hull below waterline is to be sufficiently clean to permit meaningful examination. The Classification Society is to be satisfied with the methods of localisation of the divers on the plating, which should make use where necessary of permanent markings on the plating at selected points.
The In-water Survey is to be carried out by a Surveyor who is a skilled diver and trained to carry out In-water Survey, or a qualified diver under surveillance of a Surveyor. The diver has to be employed by a firm acceptable to the Classification Society.
When professional divers are employed, the Surveyor shall be satisfied with the method of pictorial representation, and a good two-way communication between the Surveyor and divers is to be provided.
If the In-water Survey reveals damage or deterioration that requires early attention, the Surveyor may require that the ship be dry docked in order that a detailed survey can be undertaken and the necessary repairs carried out.