Dry docking and undocking SOP: block plan to refloat
A shipyard SOP for dry docking and undocking a vessel: block plan verification, controlled dewatering, a stability check, dry-period repair work, and refloat, with an owner and workload hours on every step.
How it works
Match the lanes to your own dock organization
The sample uses Dock Master, Planning, Mechanical, QA/QC and Vessel / customer. If your yard splits mechanical from electrical and hydraulic repair capability, or routes authorization through a separate dock superintendent, give each its own lane rather than folding it into Mechanical: the lane is what tells a reader who owns a step at a glance.
Replace the sample People and Workload values with your own roster and hours
Swap the named people for your actual dock master, planning lead and foremen, and set Workload to the effort each step realistically takes at your yard, not elapsed calendar time. That is what the workload BI panel totals, so placeholder hours produce a placeholder workload picture.
Write your own tolerance and stability criteria onto the decision boxes
"Vessel centered and trim within tolerance?" and "Vessel stable and correctly landed on blocks?" need numbers behind them: the centering and trim tolerance your pilots work to, and what 'correctly landed' means for the hull types you dock. A decision with no stated criterion gets answered by judgement, which is exactly what a re-dock branch exists to catch.
Add your own dry-dock work authorization gate
"Authorize repair teams to enter the dry dock" should name who actually signs it at your yard, whether that is the dock master alone or a joint sign-off with QA/QC, and what the authorization confirms: block landing verified, dock access safe, permits issued.
Extend the dry-period step for your own trade mix
"Repair work proceeds through the dry period" is deliberately one step covering every trade's dry-dock-only work. If you need visibility into hull, sea valve, propeller and rudder work separately, split it into parallel rows in the same stage rather than serializing them, and keep each on its own workload total.
Keep the final customer walk-through as its own step, not a note on refloat
"Final underwater checks and customer walk-through" is the customer's own sign-off before departure. Keeping it as a separate row after "Flood the dock and refloat the vessel" gives you a distinct approval and a distinct owner, rather than bundling customer acceptance into the refloat itself.
Frequently asked questions
Why does this SOP have three separate decision points instead of one docking step?
Because a docking fails at three different moments, not one: the block plan can be wrong before the vessel ever enters the dock, the vessel can settle off-center or out of trim as the water drops, and the landing itself can be wrong once the dock is dry. Each decision is placed at the moment the corresponding mistake becomes checkable, and each branches back to rework rather than forward to a note, because catching a bad block plan before positioning is far cheaper than catching it after the dock is dry.
What do the People and Workload columns do on this chart?
Each step carries the person or people accountable for it and a Workload figure in hours representing the effort that step actually takes, not the calendar time it spans. The workload BI panel reads those two columns across the whole chart to total effort by person and by stage, so a planning lead can see, for example, that the mechanical foreman is already carrying six hours of dry-period work on one docking before committing them to a second.
What happens if the block plan doesn't match the vessel's keel and bilge profile?
The decision "Block plan matches keel and bilge profile?" routes a mismatch to "Revise block layout with vessel's chief engineer" and back to the same check, rather than letting positioning start on an unverified plan. Blocks are physically positioned only after the plan passes this check, which is what keeps a hull penetration or sea chest from ending up resting on a block it was never designed to carry.
Who authorizes entry to the dry dock, and who authorizes undocking?
They're separate gates with separate owners on this chart. "Authorize repair teams to enter the dry dock" opens the repair period once the vessel is confirmed stable and correctly landed. "All dry-dock work complete and dock clear?" is the later, separate gate that decides whether undocking can begin, and it branches to "Extend dry period and notify customer of revised schedule" when work isn't finished rather than letting flooding start on an incomplete dock.
Can this SOP be adapted for a floating dock or a syncrolift instead of a graving dock?
Yes, the stage structure carries over: block plan, positioning, controlled dewatering (or lift) with a landing check, an authorized work period, and a dock-clear decision before returning the vessel to the water. What changes is the mechanics inside a few steps, positioning blocks on a floating dock's pontoon deck or setting a syncrolift's transfer sequence, so revise those specific rows rather than the overall sequence.