M500-3.2.3

Dry-docking and undocking - procedure and precautions, with or without damage

Sign in to track progress

You are alongside in a commercial port. Your manager calls: the yard has a slot tomorrow and wants to bring the vessel in. You know the vessel has sustained a minor grounding — a suspected dent in the shell plating forward, no apparent flooding — but the full extent is unknown. You are the Master. The decision to dock, and the safety of the vessel and everyone on it throughout the process, is yours.

Before You Enter Dry Dock — the Master's Assessment

Before any docking, you must satisfy yourself the vessel is fit to enter. With damage, this means:

  • Assess hull integrity: is the damage progressive? Is there any ingress under static or dynamic loading?
  • Review the vessel's stability booklet and obtain the docking stability booklet or trim-and-stability data specific to the block plan the yard will use.
  • Confirm the docking plan with the Dock Master: block positions, keel clearances, approach draught, any soft patches or temporary repairs that must be disclosed.
  • Notify your Classification Society surveyor. With suspected shell plating damage, the surveyor should attend. The yard must know before blocks are placed — a depressed plate over a keel block is a stability catastrophe.
  • In a damage scenario, consider: can the vessel safely reach the yard under her own power? Is an escort tug warranted? Is the damage aft of or near the collision bulkhead?

The Docking Evolution

As the vessel enters the dock and water is pumped down, the hull progressively transfers load onto the blocks. The critical moment is first contact — from that point, the vessel is no longer freely floating and underwater damage will be exposed. You or a responsible officer must be present and in communication with the Dock Master throughout.

Key precautions:

  • Agree a signal or stop-pump protocol with the Dock Master before pumping begins — if the vessel lists, develops a trim inconsistent with the block plan, or shows signs of instability, pumping stops immediately.
  • All sea cocks closed as agreed with the yard before pumping.
  • Personnel clear of the bilges and below spaces during keel contact.
  • Fire hoses rigged; the dry dock environment introduces significant fire risk during subsequent work.

Undocking

Do not accept the vessel back until you are satisfied repairs are complete to the surveyor's satisfaction and the Class Certificate (or interim notation) is in order. Before flooding:

  • All sea cocks and hull penetrations verified closed or as required for flooding.
  • Confirm stability data is still valid with any repairs made.
  • Flooding should be controlled; check for ingress from shell fittings as water rises.
  • At float-off, verify the vessel is upright, on even keel within acceptable limits, and all systems are functional before leaving the dock.

Command Responsibility

The Master cannot delegate the decision to enter a damaged vessel into dry dock. You hold the safety case. If you are not satisfied — with the survey data, the block plan, the yard's understanding of the damage — you decline or delay until you are.

Practice questions

oralcore

Your vessel has sustained a grounding and you suspect shell plating damage forward. The yard has a slot available tomorrow. Walk me through what you do before you take the vessel into dry dock.

recallcore

Why is first contact with the keel blocks a critical point during the docking evolution?

scenariocore

Midway through pumping down, the vessel develops a list to starboard of about three degrees that was not anticipated in the docking plan. What do you do?

scenariocore

Repairs are complete and the yard wants to flood up and undock. What checks do you make before you accept the vessel back afloat?

recallstretch

You are the Master and the dock manager tells you the yard has assessed the damage and is happy to proceed with the block plan they have on file. What is your response?

Independent preparatory study aligned to the MCA Master (Yachts less than 500 GT) oral examination syllabus. Not an MCA-approved course and confers no credit toward a Certificate of Competency.