7 Things We Check Before Drydocking

Drydocking is one of the most important technical and financial events in a vessel’s operating life.

It is also a period when incomplete preparation can become expensive. Work that was not properly identified before arrival may lead to additional repairs, extended yard time, delayed redelivery or decisions being made under pressure.

A successful drydock therefore starts well before the vessel reaches the yard.

The objective is not simply to prepare a repair list. It is to understand the vessel’s condition, identify the work that genuinely needs to be done, establish priorities and ensure that the necessary technical, commercial and logistical arrangements are in place.

Here are seven areas that deserve particular attention.

𝟏. 𝐂𝐥𝐚𝐬𝐬 𝐚𝐧𝐝 𝐬𝐭𝐚𝐭𝐮𝐭𝐨𝐫𝐲 𝐬𝐮𝐫𝐯𝐞𝐲 𝐫𝐞𝐪𝐮𝐢𝐫𝐞𝐦𝐞𝐧𝐭𝐬

The first step is to establish exactly what surveys, inspections and certifications are due.

This includes reviewing the vessel’s survey status, outstanding conditions of class, recommendations, statutory survey requirements and any items that must be completed during the docking period.

The important point is to identify the full scope early.

A missed survey requirement can create complications once the vessel is already in the yard, particularly if additional inspection, repairs or specialist attendance becomes necessary.

The key question: What must be completed during this docking, and what evidence will be required before the vessel can return to service?

𝟐. 𝐇𝐮𝐥𝐥 𝐜𝐨𝐧𝐝𝐢𝐭𝐢𝐨𝐧 𝐚𝐧𝐝 𝐬𝐭𝐞𝐞𝐥 𝐫𝐞𝐧𝐞𝐰𝐚𝐥𝐬

Hull repairs can have a significant impact on both the budget and the docking schedule.

Previous thickness measurements, coating condition, corrosion records, damage history and earlier repair reports should be reviewed before preparing the work specification.

Particular attention should be given to areas with known corrosion, recurring defects, previous steel renewals or evidence of localised damage.

Where further examination is required, the inspection plan should be agreed in advance so that the necessary measurements and repair decisions can be made without avoidable delay.

The aim is not to assume that every suspected defect requires steel renewal. It is to identify the areas of uncertainty and establish how they will be assessed.

The key question: What do the vessel’s records tell us about the hull’s condition, and which areas need closer examination once the vessel is in drydock?

𝟑. 𝐌𝐚𝐢𝐧 𝐦𝐚𝐜𝐡𝐢𝐧𝐞𝐫𝐲 𝐚𝐧𝐝 𝐚𝐮𝐱𝐢𝐥𝐢𝐚𝐫𝐲 𝐞𝐪𝐮𝐢𝐩𝐦𝐞𝐧𝐭

Drydocking provides an opportunity to address machinery defects and planned maintenance that may be difficult to complete during normal operations.

The preparation should consider maintenance history, recurring failures, equipment condition, outstanding defects and the manufacturer’s recommendations.

For the main engine, auxiliary engines, pumps, valves, coolers and other critical equipment, the work list should distinguish between:

Mandatory or time-critical maintenance.

Known defects requiring repair.

Equipment showing signs of deterioration.

Work that can be deferred safely, subject to technical assessment.

This distinction helps prevent the repair specification from becoming an unprioritised collection of jobs.

The key question: Which jobs are essential for reliability and safe operation, and which can be planned for a later maintenance window?

𝟒. 𝐏𝐫𝐨𝐩𝐞𝐥𝐥𝐞𝐫, 𝐫𝐮𝐝𝐝𝐞𝐫 𝐚𝐧𝐝 𝐮𝐧𝐝𝐞𝐫𝐰𝐚𝐭𝐞𝐫 𝐞𝐪𝐮𝐢𝐩𝐦𝐞𝐧𝐭

The underwater inspection is a central part of drydock preparation.

The planned scope should consider the propeller, shafting arrangements where applicable, rudder, bearings, seals, sea chests, gratings, valves and other underwater fittings.

Previous vibration, propulsion-performance or steering-related issues may indicate areas requiring additional attention.

The vessel’s operating history can be particularly useful here. A defect that appears minor during a voyage may warrant closer examination when the relevant components are accessible.

Inspection findings should be evaluated against applicable limits and manufacturer or class requirements before repair decisions are finalised.

The key question: Are there performance symptoms or historical defects that should influence the underwater inspection scope?

𝟓. 𝐂𝐚𝐫𝐠𝐨 𝐞𝐪𝐮𝐢𝐩𝐦𝐞𝐧𝐭 𝐚𝐧𝐝 𝐯𝐞𝐬𝐬𝐞𝐥-𝐬𝐩𝐞𝐜𝐢𝐟𝐢𝐜 𝐬𝐲𝐬𝐭𝐞𝐦𝐬

The work list must reflect the type of vessel and the demands of its trade.

For a dry bulk carrier, this may include hatch covers, hatch-cover operating systems, cargo cranes where fitted, ballast arrangements and cargo-hold condition.

For oil and product tankers, attention may include cargo pumps, valves, pipelines, inert gas equipment and associated safety systems.

Chemical and gas carriers may require additional consideration of cargo-handling equipment, compressors, specialised valves, instrumentation and systems specific to the cargoes carried.

A generic drydock specification is rarely sufficient for every vessel.

The scope should be based on the vessel’s actual equipment, operating history, defects and intended service after docking.

The key question: Which cargo-related systems are essential to the vessel’s next employment, and what needs to be inspected, repaired, tested or certified before redelivery?

𝟔. 𝐑𝐞𝐩𝐚𝐢𝐫 𝐬𝐩𝐞𝐜𝐢𝐟𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬, 𝐦𝐚𝐭𝐞𝐫𝐢𝐚𝐥𝐬 𝐚𝐧𝐝 𝐜𝐨𝐧𝐭𝐫𝐚𝐜𝐭𝐨𝐫𝐬

Once the work has been identified, the next challenge is making sure that it can be executed efficiently.

Repair specifications should be clear enough for the yard and contractors to understand the required work, inspection criteria and expected completion standards.

Materials, spare parts, specialist services and any required maker attendance should be identified as early as possible.

This is particularly important for equipment with long lead times or repairs that depend on inspection findings.

Where the final scope cannot be confirmed until the vessel is in drydock, the likely scenarios should be considered in advance. This helps the team understand the possible cost and schedule implications before a decision becomes urgent.

The key question: Do we have the information, materials, people and decision-making arrangements needed to complete the planned work without unnecessary waiting?

𝟕. 𝐁𝐮𝐝𝐠𝐞𝐭, 𝐬𝐜𝐡𝐞𝐝𝐮𝐥𝐞 𝐚𝐧𝐝 𝐜𝐨𝐧𝐭𝐢𝐧𝐠𝐞𝐧𝐜𝐲 𝐩𝐥𝐚𝐧𝐧𝐢𝐧𝐠

A drydock budget should reflect more than the estimated price of the initial repair list.

It should also consider likely additional work, technical uncertainty, contractor availability, materials, inspection findings and the operational consequences of an extended stay.

The schedule needs similar attention. Critical-path jobs should be identified, dependencies understood and responsibility for approving additional work clearly established.

A contingency is not an admission that planning has failed. It is recognition that some conditions cannot be fully assessed until the vessel is inspected.

Good preparation makes these uncertainties visible and gives the owner and technical team a structured way to respond.

The key question: If the inspection reveals additional work, can the team assess its technical necessity, cost and time impact quickly enough to make an informed decision?

Preparation is what makes the difference

A well-managed drydock is not simply one in which every planned job is completed.

It is one in which the vessel’s condition is understood as far as reasonably possible, critical work is prioritised, resources are arranged in advance and unexpected findings are managed through a clear decision-making process.

The quality of the outcome depends on the connection between technical records, onboard observations, survey requirements, repair specifications and communication between the vessel, ship manager, owner and yard.

No checklist can eliminate every uncertainty. However, a disciplined preparation process can reduce avoidable surprises and help ensure that time and money are spent on the work that matters most.

𝐓𝐡𝐞 𝐦𝐨𝐬𝐭 𝐮𝐬𝐞𝐟𝐮𝐥 𝐪𝐮𝐞𝐬𝐭𝐢𝐨𝐧 𝐭𝐨 𝐚𝐬𝐤 𝐛𝐞𝐟𝐨𝐫𝐞 𝐝𝐫𝐲𝐝𝐨𝐜𝐤𝐢𝐧𝐠 𝐢𝐬 𝐧𝐨𝐭 𝐬𝐢𝐦𝐩𝐥𝐲, “𝐖𝐡𝐚𝐭 𝐰𝐨𝐫𝐤 𝐬𝐡𝐨𝐮𝐥𝐝 𝐰𝐞 𝐝𝐨?” 𝐈𝐭 𝐢𝐬, “𝐖𝐡𝐚𝐭 𝐝𝐨 𝐰𝐞 𝐤𝐧𝐨𝐰 𝐚𝐛𝐨𝐮𝐭 𝐭𝐡𝐞 𝐯𝐞𝐬𝐬𝐞𝐥, 𝐰𝐡𝐚𝐭 𝐫𝐞𝐦𝐚𝐢𝐧𝐬 𝐮𝐧𝐜𝐞𝐫𝐭𝐚𝐢𝐧, 𝐚𝐧𝐝 𝐰𝐡𝐚𝐭 𝐦𝐮𝐬𝐭 𝐛𝐞 𝐫𝐞𝐚𝐝𝐲 𝐛𝐞𝐟𝐨𝐫𝐞 𝐭𝐡𝐞 𝐯𝐞𝐬𝐬𝐞𝐥 𝐚𝐫𝐫𝐢𝐯𝐞𝐬?”

That is where effective drydock management begins.