Shipbuilding and marine fabrication · reference card
Weld monitoring for shipbuilding
High-volume welding under classification-society rules. The codes that apply, the four monitoring pain points that cost yards most, and which Therness signal addresses each.
- Industry
- Shipbuilding and marine fabrication
- Dominant processes
- Flux-cored arc welding on panel lines and block assembly; Submerged arc welding on long butt seams and stiffener fillets; Gas metal arc welding for erection and outfitting; Stud welding for outfitting attachments
Shipbuilding is the volume case for weld monitoring. A yard produces more welded metres in a week than most fabricators produce in a year, spread across panel lines, block shops, subcontractors and open berths — and the quality system has to hold across all of it while surveyors sample only a fraction.
That ratio is the whole argument. When inspection is necessarily a sample, the value of a continuous record is not that it replaces the sample but that it tells you where the sample should be taken, and what the rest of the population looked like.
Environment does the rest of the work. Most of the porosity a yard sees is not a procedure problem; it is a draught, a damp morning, or a gas hose that had been fine yesterday. Those conditions are invisible in a settings sheet and obvious in a gas-flow and thermal record taken at the torch, which is why the same joint can pass all summer and fail in February.
Governing codes
| Code | Why it applies |
|---|---|
| Classification society rules | DNV, Lloyd's Register, Bureau Veritas, ABS and RINA each publish rules for hull materials and welding that the yard's approvals rest on. |
| ISO 5817 | The quality-level standard the rules and contracts usually point to for steel hull joints. |
| ISO 3834-2 | The quality-system declaration behind a yard's welding approvals and its subcontracting arrangements. |
| IACS unified requirements | Common ground between societies on hull materials and welding, adopted into each society's own rules. |
Monitoring pain points
| Pain point | Consequence | Signal that sees it |
|---|---|---|
| Site conditions vary faster than procedures do | Draught and damp on an open berth produce porosity in joints that are clean under cover, with no change in settings. | Gas flow measured at the torch and logged with the weld, so the environment is visible in the record. |
| One-sided welding on ceramic backing hides its own root | Root imperfections are found by examination after the panel has moved on to the next station. | Thermal signature of the root run captured while the run is being made. |
| Distortion accumulates across a large panel | Straightening work is added late, absorbing labour that was never planned into the block. | Arc energy and interpass records per seam, which is where accumulated heat originates. |
| Traceability spans many welders, shifts and subcontractors | Reconstructing who welded what, and under what conditions, becomes the slow part of a class survey. | Weld identifier, operator and process record joined automatically instead of transcribed. |
What that means for the cell
- HeatCam IR-C thermal weld camera Thermal evidence per seam on panel-line volumes, where inspecting every joint by hand is not affordable.
- AI weld monitoring platform The route for turning per-weld signals into evidence a class surveyor can be shown.
Questions from shipbuilding and marine fabrication
Is weld monitoring accepted by classification societies as evidence?
Societies accept the records a yard keeps as part of its approved quality system; they do not accept monitoring in place of the survey and testing their rules require. Treat it as evidence that supports an approval, and agree the record format with the society in advance.
What makes shipyard welding different from shop fabrication for monitoring purposes?
Volume and environment. The joint count is high enough that per-weld manual inspection is not affordable, and much of the work happens where wind, damp and temperature move faster than any procedure revision.
Bring the evidence forward, not the inspection
Therness measures what happens while the arc is running — parameters, thermal signature, per-weld records — so the problems on this page surface on the shift that made them.
