Everything inspection divers need to know before renewal — what to study, how the process works, and how to prepare from offshore.
One rotation you're sitting your CSWIP exam, the next you're looking at an expiry date and realising you haven't reviewed the theory since your original course.
That is the reality for most inspection divers. The offshore work is familiar — the theory has faded. This guide covers what the renewal process involves, what topics to revisit, and how to prepare efficiently from offshore.
CSWIP underwater inspection certifications are valid for 5 years. Recertification requires an examination every 5 years — the same process each cycle.
| Requirement | Detail |
|---|---|
| Certificate validity | All CSWIP underwater certificates — 3.1u, 3.2u and 3.4u — valid for 5 years from date of issue |
| Recertification exam | Examination required every 5 years. Contact TWI Examinations at trainexam@twitraining.com to book |
| Work experience | Documentary evidence of work experience and diving record must be provided at examination. Sufficient evidence may exempt you from part of the exam |
| Eyesight test | Recent eyesight test certificate to standards in the relevant CSWIP scheme document required |
| Renewal window | Applications accepted up to 6 months before expiry. Certificates take several weeks to issue — don't leave it late |
| Lapsed certificate | Contact TWI Certification Ltd directly on +44 (0)1223 899405 |
Request hand-to-hand courier delivery for your certificate. TWI offers this at additional cost — worth every cent. CSWIP certificates sent by standard international post have been known to go missing, and replacing a lost certificate is slow and painful. Ask TWI about this when submitting your renewal application.
A CSWIP refresher is structured revision completed before renewing or re-sitting an inspection certification. TWI and approved training centres offer official one-day refresher courses covering practical and theoretical elements.
An online CSWIP refresher lets you review key theory topics, practise exam-style questions, and rebuild confidence — from anywhere, at any time.
A 3.1u refresher focuses on the core knowledge expected from divers performing underwater visual inspection.
Structure types, jacket configurations, platform zones, and structural terminology used in inspection reporting.
Static, dynamic, cyclic and fatigue loading — and how loading affects what divers look for during inspection.
Electrochemical corrosion, the galvanic series, dissimilar metal cells, crevice and pitting corrosion mechanisms.
Sacrificial anode systems, impressed current CP, CP readings, anode condition assessment, and correct potential values.
Visual defect identification, correct CSWIP terminology, causes of defects, and how to describe them in reports.
Ultrasonic thickness measurement principles, equipment use, calibration, and recording procedures.
Underwater photography principles, CCTV commentary technique, framing, scale, and documentation standards.
Data sheet completion, reporting methods, anomaly descriptions, and documentation standards for underwater inspection.
The 3.2u level builds directly on 3.1u. A 3.2u refresher covers all 3.1u foundations plus the additional NDT techniques introduced at this level.
MPI principles, magnetisation techniques, fluorescent ink, UV light requirements, sensitivity checks, and coil method procedures.
A-scan interpretation, probe types, calibration procedures, distance amplitude correction, and defect sizing.
Calibration blocks, sensitivity settings, reference standards, and the importance of equipment checks before inspection.
Grinding requirements, profile specifications, surface finish standards, and what examiners assess during the practical.
Cleaning standards, surface finish requirements before NDT, and how surface condition affects inspection results.
Inspection quality control, procedure compliance, documentation requirements, and reporting standards at 3.2u level.
The 3.4u Underwater Inspection Controller certification carries its own renewal requirements. A 3.4u refresher focuses on planning, QA, and management knowledge.
Work pack preparation, inspection scheduling, diver and ROV capability decisions, ALARP principles, and briefing scope.
Quality assurance frameworks, documentation systems, anomaly-based reporting, and verification body requirements.
Data sheet design, video log design, reporting formats, and how inspection data is processed and stored.
Structured written responses, anomaly descriptions, and how marks are awarded in the 3.4u written exam papers.
Capability and limitation assessment for divers and ROVs, when each applies, and how to justify method selection.
Isometric drawing reading, structural drawings, and extracting inspection-relevant information from technical drawings.
Most divers preparing for renewal are not short on offshore experience. The problem is that exam-level theory fades when it isn't used day-to-day.
The correct CSWIP terminology for defect types, corrosion mechanisms, and structural terms gets rusty without regular use.
Divers know the job. The exam asks about the science behind it — electrochemistry, metallurgy, physics of UT.
The original course notes are a 300-page manual. Most divers don't know what to prioritise or how to structure self-study.
Renewal deadlines often land during rotations. Finding resources that work from offshore or short turnaround leave is difficult.
NDTPrep courses are built for working offshore inspection divers. Study between shifts, during transit, or on leave — no fixed schedule required.
Do not skip these steps even as an experienced inspector — they reset your terminology foundation.
Built by a diver, for divers. Study from anywhere — offshore, on leave, or between rotations.
NDTPrep is an independent exam preparation platform. Not affiliated with or endorsed by TWI Certification Ltd or CSWIP. All certification training and examinations are administered by approved CSWIP training centres. Always confirm current renewal requirements directly with TWI Certification Ltd.