Guides · 5 min read
Dry-dock budgeting: why dockings overrun, and how to control variations
Most docking overruns are decided before the ship enters the dock. How to build the budget, price the unknowns at tender and run variations day by day.
A docking is a project with a hard deadline, a shared budget, a yard that earns more when the scope grows, and a class surveyor at the end who will not sign until the work is done. Superintendents know the feeling of day 9: the hull is blasted, the steel is worse than the gauging said, the propeller polisher is two days late, and the owner wants a number by Friday.
There is no reliable public statistic on how often, or by how much, dockings overrun, and we will not invent one. What experienced superintendents agree on is where overruns come from, and that most of them are decided months before the ship enters the dock. This article sets out the survey rules that fix the timing, how to build a budget that survives the yard, and a variation process that keeps the final invoice close to the plan.
The rules that set the date
The docking date is not a commercial choice alone. Under SOLAS Chapter I, regulation 10, a cargo ship needs a minimum of two inspections of the outside of the bottom during any five-year period, and no more than 36 months between any two. Under the harmonized system of survey and certification (HSSC), surveys run on a five-year cycle: annual surveys within three months either side of each anniversary, an intermediate survey around the second or third anniversary, and a renewal survey before the certificate expires.
In practice one docking goes with the renewal (special) survey and one with the intermediate survey. Some ships may replace an intermediate docking with an in-water survey, under flag and class conditions that vary with age and type. Check them early; an in-water survey approved in principle but refused on detail puts a docking back into the plan with no budget.
Two other rules now shape docking scope. The Hong Kong International Convention on ship recycling entered into force on 26 June 2025, and the Inventory of Hazardous Materials must be kept up to date, which matters whenever a docking adds or removes equipment. And the ballast water D-2 standard has applied to all ships since September 2024, so any outstanding treatment work belongs in the next docking plan, not the one after.
Why dockings overrun
The illustration shows the usual shape of the drift. The largest pieces are the ones a firmer specification could have priced before tender.
| Cause | What happens | Could it have been priced at tender? |
|---|---|---|
| Steel growth | Gauging was old or thin; blasting reveals more renewal | Yes: recent gauging, and a unit price per kg for extra steel |
| Extra dock days | Scope grows, or a critical item is late | Partly: a daily rate for extra days, and critical path agreed |
| Class findings | The surveyor finds items not in the specification | Partly: last survey reports and open conditions in the specification |
| Owner's additions | "While she is in dock" jobs added on the day | Yes: a reserve list priced at tender, released by approval |
| Price variations | Unit rates applied to quantities not in the contract | Yes: a full schedule of unit rates in the contract |
| Owner's supply late | Spares, paint or a service engineer arrives late | Yes: a delivery plan, tracked weekly from week minus 12 |
The pattern is clear: overruns mostly come from unknown quantity, not unknown price. The cure is to turn unknown quantities into agreed unit rates before the yard is chosen, and to find as many quantities as possible before the ship arrives.
Build the budget in layers
A docking budget that survives the yard has four layers. Keep them separate in the tender comparison and in the final account, so you can see which layer moved.
| Layer | What is in it | How it is priced |
|---|---|---|
| Yard fixed | Docking and undocking, dock days, services: electricity, cooling water, fire watch, cranes, garbage | Lump sums and daily rates from the tender |
| Specified work | Hull preparation and painting, valves, sea chests, propeller and shaft work, tanks, machinery jobs | Quantity × unit rate, from the specification |
| Provisional work | Steel renewal, extra blasting, extra pipe, extra days | Unit rates agreed at tender; quantity unknown |
| Owner's costs | Owner's supply, class and flag fees, service engineers, superintendent attendance, off-hire, deviation fuel | Owner's own quotes and estimates |
Then add a contingency that is an explicit number, not a hope. A useful discipline is to set a point, such as 70% of the contingency spent, at which the superintendent goes back to the owner with a revised forecast before any further variation is approved. The figure is an internal control, not an industry norm; choose your own and write it down.
Off-hire is part of the budget
The yard invoice is not the whole cost. Every extra day in dock is a day off hire, and for most ships that is the largest cost of an overrun. Put the ship's daily earnings next to the yard's daily rate in the budget, so a decision to extend by two days is seen at its real price.
The specification, twelve months out
| When | Technical | Commercial and owner |
|---|---|---|
| 12 months out | Collect survey status, open class items, last docking report, recent gauging | Agree budget envelope and docking window with commercial |
| 9 months out | Draft specification by system, with quantities and photos | Shortlist yards; confirm owner's-supply lead times |
| 6 months out | Final specification; provisional items with unit rates; reserve list | Tender; compare like for like, layer by layer |
| 3 months out | Order owner's supply; book service engineers | Contract with full schedule of unit rates and daily rates |
| Last month | Pre-docking meeting; critical path agreed with the yard | Confirm off-hire dates with charterers |
A specification is only as good as its quantities. "Renew steel as required" is not a specification; it is a blank cheque. "Renew steel as required, estimated 12 tonnes, unit rate per kg agreed" is.
Control variations, day by day
Once the ship is in dock, the specification is fixed and everything else is a variation. Four habits keep variations under control:
- One variation log. Every variation gets a number, a description, the reason, the quantity, the unit rate, the total and the approver. Nothing is done without a number.
- Approval limits. The superintendent approves up to an agreed amount; above it, the technical manager; above that, the owner. The limits are set before docking, not argued on the day.
- Daily progress meeting. The yard's project manager, the superintendent and the chief engineer walk the critical path every morning, and the variation log is read at the same meeting.
- Measure before you pay. Steel is weighed or calculated from drawings, blasting area is measured, days are counted from the dock log. Each variation has evidence attached.
Close-out: the account and the record
The docking is not over when the ship floats. The final account should reconcile every line to the specification or a numbered variation, with evidence. The survey status, class reports, updated certificates, the IHM update and the photographs of work done go into the ship's record the same week, while people still remember.
| Close-out item | Why it matters |
|---|---|
| Final account reconciled to specification and variation log | Catches double charges and unapproved work |
| Class and flag reports filed; certificates updated | The next Port State officer will ask |
| Unit rates and quantities recorded per system | They become the next docking's estimate |
| Lessons list: what grew, and why | Next time, it goes in the specification |
What to do Monday
- List every ship's next bottom inspection due date against the 36-month limit and the survey windows.
- For dockings in the next 12 months, check the age of the last gauging; order new gauging where it is old.
- Put a full schedule of unit rates (steel per kg, blasting per m², pipe per metre, extra days) into every tender.
- Split each docking budget into yard fixed, specified, provisional and owner's costs.
- Set approval limits and a contingency review point, in writing, before the ship arrives.
- Add off-hire per day to every docking budget, next to the yard's daily rate.
- Start owner's-supply tracking 12 weeks before docking.
Questions and answers
How often must a ship be dry-docked?
Under SOLAS regulation I/10, a cargo ship needs at least two inspections of the outside of the bottom in any five-year period, with no more than 36 months between any two. Some may be in-water surveys, under flag and class conditions.
When does the specification start?
About twelve months before the docking, with survey status, open class items, recent gauging and the last docking report.
Why do dockings overrun?
Mostly from unknown quantities: steel growth after blasting, extra dock days, class findings, owner's additions and late owner's supply. There is no reliable public figure for how often or by how much.
How do you control variations?
One numbered variation log, approval limits set in advance, a daily progress meeting on the critical path, and evidence for every quantity before it is paid.
What should a tender include?
A like-for-like specification with quantities, and a full schedule of unit and daily rates for provisional work, so that growth is priced before the yard is chosen.
What is the real cost of an extra day in dock?
The yard's daily rate plus the ship's lost earnings for that day. For most ships, off-hire is the larger of the two. *This article explains; it is not class or flag guidance. Check your class society's rules and your flag's requirements for your ship.*
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