The Short Answer
IACS societies (DNV, Lloyd's Register, BV, ClassNK, ABS and others) do not generally prohibit used or reconditioned spares. What they require is traceability and verification: proof of what the part is, what condition it is in, and — for critical components — independent witnessing of tests. A used part with full records clears survey faster than a new part with none.
What Surveyors Ask For, by Criticality
| Component class | Typical expectation |
|---|---|
| Propulsion-critical (crankshafts, bedplates, running gear) | Dimensional records + NDT reports; class witnessing of MPI/UT commonly requested; chemical/mechanical certificates for any weld repair |
| Pressure-retaining (heads, liners, coolers) | Hydro-test certificates; wall-thickness readings where corrosion is a factor |
| Auxiliary and consumable (pumps, seals, gaskets) | Maker identification and fit-for-purpose assessment; surveyor sign-off at fitting survey |
How to Buy Class-Ready
- State the class requirement in the RFQ. "DNV-witnessed MPI required" in the first message saves weeks. Our inspection workflow (see NDT procedures) is built around witnessed testing.
- Demand the paper pack: donor identification, dimensional sheets, NDT reports with technician certification numbers, preservation records. This is the same discipline as identifying genuine OEM parts.
- Budget the surveyor. Independent IACS witnessing is arranged per job at additional cost — factor 1–2 weeks and the attendance fee into breakdown planning, or read our emergency procurement guide for compressing that timeline.
Bottom line: class societies care about evidence, not newness. Buy the evidence with the part — start with a class-stated enquiry on our contact page.
