A welder with a machine and a good hand is not the same thing as a repair class will accept. On a classed vessel, structural welding is a documented process, and the paperwork is not an afterthought — it is the part that determines whether the repair stands.
The four things every class society converges on
The major societies differ in detail and agree on substance. Whatever the flag or class, expect to satisfy all four:
- ■ Qualified procedures. A Welding Procedure Specification (WPS) covering the joint, material and position in question.
- ■ Certified welders. Individual qualification against a recognised standard, not general experience.
- ■ Recorded inspection. Someone competent signs for what was examined and when.
- ■ Traceable data per joint. Which welder, which procedure, which consumable batch, on which joint.
Procedure qualification comes before production welding
Procedure qualification testing is carried out under a recognised standard such as ISO 15614-1 or equivalent, and the mechanical test results are reviewed by the attending surveyor before production welding begins. This ordering matters. Work started ahead of that review is work that may have to be cut out.
For important structural parts, class rules generally require the work to be carried out by an approved company or workshop, not simply by a qualified individual.
Hot work permits: the part that stops the job
A hot work permit is required for any welding, cutting, grinding or brazing performed outside the designated engine room workshop. In practice the permit is where afloat repairs most often stall, because it depends on conditions rather than paperwork alone:
- ■ Atmosphere testing of the space, and re-testing at intervals
- ■ Confined space entry controls where applicable
- ■ A dedicated fire watch, during the work and after it
- ■ Isolation of adjacent tanks, cables and fuel lines
- ■ Agreement with the terminal or port authority, which may restrict hot work entirely while cargo operations are in progress
That last point catches people out. A permit the vessel is willing to issue can still be refused at berth, which is why hot work scope should be raised with the agent before arrival rather than on the day.
The documentation pack
A repair intended to satisfy class typically closes out with:
- ■ Approved Welding Procedure Specifications (WPS)
- ■ Welder Performance Qualification Records (WPQR)
- ■ Material mill test reports for inserts and doublers
- ■ Third-party or surveyor inspection reports
Assembling this after the fact is considerably harder than collecting it as the work proceeds. If the repair may later be surveyed, treat the pack as part of the job.
What to have ready before the team boards
Send the defect description with photographs, the plate or pipe material and thickness, the location and its access constraints, whether the space can be gas-freed, and whether class has already been informed. Those five items decide whether the job is a same-call repair or a dry-dock item, and they can be assessed before anyone travels.
How MARSEA supports this
Welding and fabrication at sea or in port sits within our marine engineering scope, alongside steel and pipe fabrication, with engineers available 24/7 for afloat repairs. Send the defect details with the port and ETA and we will come back on what is achievable within the call and what genuinely belongs in dry dock.