Drydockings become expensive when scope, yard, materials and survey windows are not properly aligned.
Docking plan, class scope, technical priorities, thickness measurements and material logistics.
Late yard selection, incomplete tender specifications and overly optimistic schedules.
They manage a drydock like a technical project: with milestones and a focus on bottlenecks.
A drydocking is the most expensive recurring maintenance event in a vessel’s lifecycle. Direct costs range from USD 500,000 for a straightforward intermediate survey on a mid-sized bulker to several million USD for a special survey with extensive steelwork on an older tanker. Indirect costs add further: off-hire days (typically 10-25 days), repositioning costs to the yard location, and opportunity costs from lost charter revenue.
The planning horizon should begin at least 12-18 months before the docking. During this phase, the following elements must be brought together:
Class scope: The class surveyor defines the minimum scope – depending on survey type (annual, intermediate, special/renewal) and vessel age. For a special survey on a 15-year-old vessel, the scope is typically substantial: thickness measurements of all structurally relevant areas, close-up inspections in ballast tanks and cargo holds, testing of all safety-critical systems.
Technical priorities: In parallel with class requirements, the superintendent has their own technical priorities: propeller polishing or replacement, rudder removal and bearing inspection, main engine overhaul, underwater hull painting, ballast tank coating, repair of known defects. These must be prioritised in consultation with class and the fleet manager.
Material logistics: All materials – paint, steel plates, spare parts, anodes, propeller elements – must be ordered in time and delivered to the yard. For international yards (China, Turkey, Eastern Europe), customs procedures and lead times must be factored in. Material shortages during docking are one of the most frequent causes of delays and cost overruns.
Yard selection: The choice of yard depends on availability, price, quality and geographical location. Chinese yards often offer the lowest prices but have longer lead times and require more detailed specifications. European yards are more expensive but offer shorter response times and higher quality standards for coating work. The decision must be made early, as good yards have waiting lists of 6-12 months.
The largest cost overruns during dockings arise from three factors:
Additional works (extras): When damage is discovered during docking that was not known beforehand – for instance through thickness measurements only performed in dock – additional works arise that were not included in the budget. Every additional steel repair, every additional coating area increases the bill. The best countermeasure: prior UTM and inspections to minimise surprises.
Delays: Every additional dock day costs berth fees (typically USD 5,000-15,000/day) plus off-hire. Delays result from missing materials, incomplete preliminary works, weather (for external works such as coating) and coordination issues between yard, class and operator. A clear schedule with milestones and daily progress checks reduces this risk.
Quality defects: Poor coating work that fails a few months after docking is the most expensive form of saving. The cost of a subsequent repair exceeds the cost of correct execution in dock by a significant factor. Quality control during docking – particularly DFT measurements (dry film thickness) and climate condition checks (dew point spread) – is therefore not a luxury but a necessity.
An experienced superintendent routinely plans a reserve of 15-20 per cent on the docking budget – not as a sign of inadequate planning but as a realistic acknowledgement of uncertainties.
Since class has accepted in-water surveys (IWS) as an alternative to drydocking for certain surveys, some operators use this option to reduce off-hire. An IWS can substitute for the intermediate survey provided certain conditions are met: visibility must be adequate, the underwater coating must be in acceptable condition, and all required examinations must be feasible underwater.
The limitations of IWS are clear, however: steel repairs, coating renewal, propeller removal and many mechanical works can only be performed in drydock. An IWS therefore frequently defers work scope to the next docking – resulting in a larger and more expensive scope there.
The decision for or against an IWS must therefore be viewed in context: What condition is the underwater hull in? Are steel works pending? What does the long-term fleet plan look like? Will the vessel be sold in the coming years? These questions determine whether an IWS is economically sound or merely shifts costs into the future.
A successful drydocking follows the principles of sound project management:
Scope definition (12-18 months ahead): Consolidate class requirements, technical priorities and known defects. Prepare tender documentation.
Procurement (6-12 months ahead): Issue yard inquiries, trigger material orders, monitor delivery dates. Identify and prioritise critical parts.
Detailed planning (3-6 months ahead): Create a detailed schedule with milestones. Coordinate with the class surveyor. Brief the crew on the docking procedure.
Execution: Daily progress checks. Immediate escalation upon deviations. Quality control in parallel with the works, not only at the end.
Post-docking review: Document lessons learned. Compare actual costs against budget. Prepare findings for the next docking.
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