Special Survey and Drydocking
The five-year class renewal cycle, the intermediate survey between, steel renewal risk, and what the survey bill does to a ship's market value.
The special survey is the class renewal survey a ship undergoes at five-yearly intervals, the most searching examination in the classification cycle, and it is normally combined with a drydocking so the underwater hull, rudder, propeller and sea inlets can be examined out of the water. It is the point at which deferred deterioration becomes a bill: thickness measurements taken at the survey determine how much steel must be renewed before class is maintained.
For a shipowner the survey is a commercial event as much as a technical one. An older ship approaching a special survey with heavy expected steel renewal can be worth less to a trading owner than the recycling market would pay for her, because the survey cost exceeds the earnings the remaining life would generate, and that comparison is what tips a ship toward demolition.
The full article will cover the survey cycle and its permitted windows, the relationship between the special survey, the intermediate survey and the annual survey, thickness measurement and steel renewal criteria, the alternative regimes including continuous survey of hull and machinery and in-water survey in lieu of drydocking , and how a buyer prices the next survey into a bid under ship finance and asset valuation .