Dry Dock Entry Planning
A poorly planned dry dock entry costs far more in ship downtime than it would have cost in preparation: the repair specification and shipyard coordination start months in advance, not at departure.
Operational Explanation
Entering a dry dock is an event planned well in advance (typically 6-12 months ahead), combining mandatory survey requirements (Class and statutory) with extraordinary maintenance work that cannot be carried out afloat. Poor planning almost always translates into a prolonged docking period, with significant direct costs (dock hire) and indirect costs (lost commercial earnings).
The repair specification is the central document: it must be detailed enough to allow the shipyard to correctly quote and organize resources, while remaining flexible enough to handle the additional (extra) work that almost always emerges during the in-dock inspection.
Regulatory Reference
There is no single convention dedicated to dry dock planning, but the entry must satisfy the requirements of SOLAS Chapter I, Regulation 10 (periodical inspections of the ship's bottom) and the survey requirements of the applicable Classification Society (Special/Renewal Survey, Intermediate Survey, according to the five-year cycle).
The docking plan is a class document, not a Convention one, and it is worth saying so precisely. SOLAS requires that a defined set of as-built construction drawings be kept on board and ashore — this is Regulation II-1/3-7, Construction drawings maintained on board and ashore, introduced by resolution MSC.194(80) for ships constructed on or after 1 January 2007 — and the list of those drawings is in the annex to MSC/Circ.1135: general arrangement, capacity plan, hydrostatic curves, loading manual, midship section, scantling plan, decks, shell expansion, transverse bulkheads, rudder and rudder stock, cargo hatch covers, and bilge, ballast and cargo piping diagrams. The docking plan is not on that list. The obligation to hold an approved docking plan, showing the arrangement of the blocks and the permissible loads on the keel and bilge, comes from Classification Society Rules, and it is the document on which the yard builds its block layout before the ship even enters. Asking “where does SOLAS say so” is the wrong question: the answer is that it does not, and that the document is binding anyway, by class and by contract.
In practice three checks precede entry: that the docking plan on board is the latest approved revision and consistent with structural changes made since the last docking (bulbs, sea chests added or blanked, reinforcements); that the yard has received that revision and not an archive copy; and that the planned bearing areas do not coincide with areas of low thickness found in the last UTM campaign. A mismatch between the docking plan and the actual block layout is one of the most recurrent causes of structural damage in dock, and it is discovered when the ship is already sitting on the blocks.
Scope of Application
Every ship subject to periodic survey requiring inspection of the bottom and of equipment not accessible while afloat (propellers, rudder, sea chests, cooling systems).
Procedure / How to Complete It
- Draft the repair specification well in advance, including mandatory survey requirements and planned maintenance work.
- Request quotes from multiple shipyards, verifying dock availability within the required time window.
- Coordinate with the Classification Society the surveyor's presence for surveys to be conducted in dock.
- Plan the sequence of work to minimize total time in dock, identifying work on the critical path.
- Allow a contingency margin for additional work that typically emerges during the in-dock inspection (e.g. unforeseen corrosion).
Practical Example
Example of planning: repair specification drafted 8 months before dry dock entry, including the Class special survey, sacrificial anode replacement, rudder and sea chest overhaul, with a 15% budget contingency for unforeseen additional work.
What Typically Goes Wrong
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Repair specification drafted too late or too generically | Difficulty obtaining comparable quotes and risk of underestimating time | Draft the specification well in advance and in as much detail as possible |
| No contingency margin for unforeseen additional work | Prolonged docking time with unplanned cost impact | Always allow a contingency margin in time and budget |
| Coordination with the Classification Society started only close to dry dock entry | Risk of surveyor unavailability within the required window | Coordinate the surveyor's presence well in advance, in parallel with shipyard planning |
What the PSCO Checks
Operational Tips
- Start dry dock planning at least 6-12 months before the expected window, never reduce this margin to save apparent time.
- Always allow a time and budget contingency for additional work: it almost always emerges.
- Coordinate the Class surveyor's presence in parallel with shipyard planning, not afterwards.
Preparation checklist
Educational checklist. This summary supports learning and preparation only. It does not replace the vessel’s approved procedures, manuals, statutory documents, company SMS, or applicable official requirements. Completing it demonstrates neither compliance nor readiness for an inspection: it shows that a list has been read, not that the ship is in order. Always verify the current documents carried on board.
- Repair specification drafted well in advance and in the necessary detail
- Quotes requested from multiple shipyards with verified availability
- Class surveyor's presence coordinated in advance
- Sequence of work planned to minimize the critical path
- Contingency margin allowed for additional work
- Docking plan on board in its latest approved revision and sent to the yard
- Bearing areas compared against the most recent thickness measurements
FAQ
Related Topics
Last substantive revision of this page: 13 August 2026 · page fingerprint 1dbe7ebdc363