Ship UTM Reading Map, Anomaly and Retest Report Record

Define who needs the readings and what they may decide.

Record whether the job supports class survey, owner condition assessment, repair planning, corrosion mapping, damage investigation, dry-dock scope, sale-and-purchase review or a limited engineering check. Each purpose can require a different location schedule, extent, witness route, reporting form and acceptance owner. The applicable class rules, survey programme, approved drawings and attending surveyor instructions take precedence over a generic website checklist.

Make the location reproducible without guesswork.

Before reading, assign each point to vessel, side, frame, longitudinal, strake or plate, compartment, structural member and face. Reference a controlled drawing revision and mark whether the point was planned, expanded after an anomaly or substituted because safe access was unavailable. Photographs can help orientation, but they do not replace a marked drawing and must not disclose vessel information without permission.

Do not infer nominal or renewal thickness from memory. Record the source and revision beside the point. Where class or the owner controls the location set, record additions and omissions with the person authorising them.

Trace the value through the complete measurement chain.

Record instrument, probe, serial numbers, range, resolution, calibration status, reference blocks, couplant and velocity basis. Note material and coating assumptions, surface preparation, curvature, temperature, corrosion profile and any limitation affecting coupling or echo interpretation. ISO 16809:2025 specifies principles for ultrasonic thickness determination using pulse time of flight; it does not itself replace the vessel-specific survey programme or acceptance criteria.

If through-coating mode, multiple-echo technique or a correction is used, state it. Retain screenshots or A-scan evidence when required by the method or reviewer. A stable numerical display does not prove the correct back-wall echo was selected.

Keep the first value, confirmation and disposition together.

Record the initial reading, repeated reading, retained value and reason for any rejection. Include units, instrument setup ID, operator, time and local condition. Where pitting or uneven corrosion is present, define how the reported value represents the agreed area and do not silently average away a local minimum.

Report factual thickness separately from diminution, remaining percentage, corrosion rate or renewal assessment. Derived conclusions require a documented nominal-thickness source, calculation rule, previous comparable record and authorised acceptance basis.

Escalate unusual readings without overwriting them.

An anomalous value can arise from real wastage, pitting, lamination, coating, poor coupling, wrong velocity, curvature, geometry or an incorrect location reference. Preserve the original record, repeat after a controlled setup check, move to adjacent points if authorised, and document the reviewer decision. Do not delete the first value because the later reading looks more convenient.

Repair or steel-renewal decisions belong to the responsible owner, yard, designer, class surveyor or other authorised reviewer. Vessel Doctor should not imply class approval, recognised thickness-measurement-company status or acceptance unless documented for the exact entity and scope.

Compare only genuinely comparable readings.

A post-cleaning, post-repair or verification reading should reference the same drawing, point, surface, side, probe/setup and reporting rule. If the original point no longer exists after renewal, map the new plate and clearly state that it is a replacement baseline rather than a repeated measurement of the old material.

For trend analysis, confirm that previous reports used compatible location IDs, nominal-thickness sources and methods. Apparent change smaller than the combined measurement and location uncertainty should not be presented as a confident corrosion rate.

Release a traceable record, not an unsupported approval.

• Identify vessel, scope, date, location, drawing revision and governing instruction.
• List personnel, witness, instrument, probe, calibration and field checks.
• Show point IDs and all retained readings with units and local conditions.
• Keep anomalies, exclusions, substitutions and expanded gauging visible.
• Separate measured values from calculations, interpretation and acceptance decisions.
• Attach marked plans, photographs or screenshots only with permission.
• Record revisions, reviewer comments and final distribution.

Use the current measurement principle and the applicable vessel rules.

• ISO 16809:2025 covers ultrasonic thickness determination using pulse time of flight.
• IACS Recommendation 77 Rev.4 addresses surveyor control of the thickness-measurement process.
• IACS Unified Requirements Z provides the current society-level survey-requirement route; the applicable member society rules and instructions must still be checked.

IACS publishes requirements and recommendations; it does not approve suppliers. Confirm the current class, flag, owner and contract requirements before attendance.