Anchor and Chain Cable Survey
An anchor and chain cable survey connects equipment examination, wear measurements and component identity with service condition. The survey helps identify defects, support renewal decisions and make the equipment returned on board verifiable.
Operational Explanation
The anchor grips the seabed; the chain cable connects it to the vessel through links and connecting accessories. The assembly also depends on shackles, pins and securing arrangements: a chain of sufficient diameter can still have a damaged connection. The chain stopper holds the chain and relieves the windlass load in the intended arrangement. Wärtsilä, Anchor; Wärtsilä, Chain stopper.
During a survey, ranging means laying out the chain to make it accessible; examination assesses condition; gauging measures dimensional wear. These provide different evidence: a gauging report does not replace examination, while visual examination alone does not demonstrate remaining diameter.
| Object | Evidence to connect |
|---|---|
| Anchor and chain connection | Identity, condition, deformation and relevant fastenings. |
| Links and joining accessories | Local wear, damage, stud integrity and connections. |
| Stopper, hawse pipes, chain locker and end attachment | Condition of associated components and evidence within the survey scope. |
The report should trace each reading to the side, chain length and point on the examined link. Continuity between finding, any renewal and refitting prevents a correct reading from being attributed to the wrong component. IACS UR Z7, §2.2.4.
Regulatory Reference
Applicable class Rules and IACS UR A1.6. The Rules define the survey; A1.6 sets the wear criterion for stud-link chain cables for bower anchors. W18 covers manufacture, testing and certification of chains and accessories.
A1.6 concerns stud-link chain cables for bower anchors. Mean diameter at the most worn section is the average of the minimum diameter and the perpendicular diameter in that same section. Compare it with the required nominal diameter: do not average several links to conceal a worn location. IACS UR A1 Rev.8 (June 2023), §A1.6.
Calculation example: required nominal diameter 50 mm, with perpendicular readings of 43 and 45 mm at the most worn section. Their mean is 44 mm, a 12% reduction: the renewal criterion is reached. Class determines the affected length and components to renew; acceptable diameter does not exclude other defects. IACS UR A1.6: worked example.
UR Z7, §2.2.4, requires anchors and chain cables to be ranged and examined at Special Survey, with their complement and condition verified and associated components examined. Gauging is included from the second Special Survey. The IACS catalogue identifies Z7 Rev.29 Corr.1 (May 2024) and A1 Rev.8 (June 2023); apply the society Rules and surveyor directions to the particular vessel. The paragraph does not prescribe a universal link-by-link sampling pattern. IACS UR Z7, §2.2.4.
For replacements, W18 distinguishes markings, grade and certification documents. Dimensional correspondence alone does not demonstrate the suitability of a replacement component. IACS UR W18, §§4.4–4.5 and 5.4–5.5.
Scope of Application
This card explains surveys of bower anchors and their chain cables. Equipment type, grade, required nominal diameter, survey number, damage/renewal history and applicable Rules define the case.
The A1.6 criterion does not automatically extend to offshore chains, permanent moorings, wire cables or studless chain. The surveyor determines necessary further investigation; this card does not authorise movement, disconnection, repair or return to service.
Procedure / How to Complete It
- Define the scope. Compare survey status, Rules, previous reports and open defects; agree examinations and measurements with class.
- Prepare identity and access. Make sides, chain lengths and components recognisable; plan movement, cleaning and access through vessel/yard procedures and responsibilities.
- Collect distinct evidence. Record examination of anchors, links and accessories; where required, connect measurements, location and applicable nominal diameter.
- Interpret the findings. Calculate mean diameter in the same section under A1.6; report defects other than dimensional wear as well.
- Follow renewal and refitting. Identify replacements, retain their documents and markings, and record checks and the class outcome.
Practical Example
Teaching example: the report gives a mean diameter of 44 mm for a length with a required nominal diameter of 50 mm, but does not identify the link and measured section. The 12% reduction calculation is correct; the finding is not yet traceable. Complete its identification and present it to class together with the examination of connections and proposed renewal. A photograph of a new chain length without a connection to the removed component does not close this gap.
What Typically Goes Wrong
The common difficulty is losing the connection between component, measurement and decision: an isolated mean value does not locate the wear or demonstrate that connections are sound. A physically completed replacement still needs documentation and verification.
Common Mistakes Mistake Library
| Mistake | Consequence | How to Avoid It |
|---|---|---|
| Use an average of several links to assess the most worn point. | A local defect may be concealed and the length remain in service without proper assessment. | Record the two perpendicular readings in the same most worn section, identifying the location. |
| Accept the chain solely because its diameter is sufficient. | Damage, deformation or connection defects may remain open. | Distinguish condition examination from the dimensional criterion. |
| Fit a replacement without connecting marking and certificate. | Grade, dimensions and component identity are not demonstrated. | Verify and retain correspondence between the item, documents and installed length. |
| Assume identical link-by-link gauging at every docking. | An invented schedule may replace the actual survey scope. | Define measurement extent from Rules, survey number and surveyor directions. |
What the PSCO Checks
Operational Tips
- Prepare a recognisable chain-length map and retain the same identification before and after renewals.
- Separate dimensional findings, other defects, proposed work and accepted outcome in the report.
- Keep original measurements and component history; document examination limitations as well.
Preparation checklist
- Survey number and scope confirmed with class.
- Anchors, lengths and accessories identifiable; nominal diameter and grade available.
- Access, cleaning and movement planned within the authorised process.
- Examinations and measurements traceable; defects and renewals connected to their outcome.
- Replacement documents and final status available.
FAQ
Related Topics
Certified substantive revision: 13 October 2026 · page fingerprint 8642253403b2