GUIDANCE MANUAL FOR TANKER STRUCTURES, CONSOLIDATED EDITION 2025-26

This consolidated edition combines in one guidance manual the various sources of information necessary for assessing the condition of the ballast tanks, cargo tanks and structure of tankers in service. While the original manual mainly addressed the conventional single hull tanker, this revision includes IACS Recommendation No. 72: Confined Space Safe Practice - Rev.4 2025 and IACS Unified Requirements (UR) Survey and Certification: Z10.4 Hull Surveys of Double Hull Oil Tankers (Rev.18 Feb 2023), where changes introduced in Rev.18 are to be uniformly applied by IACS Societies for surveys commenced on or after 1 July 2024.

This Guidance Manual has been updated to provide a comprehensive overview of:

- IACS requirements for Special, Annual and Intermediate Surveys

- survey preparation, including a review of requirements, safety aspects, equipment and details of carrying out and reporting different types of surveys

- thickness measurements

- technical background and awareness of structural defects in terms of the effects on local strength or overall structural integrity

- basic maintenance and repair guidelines are provided along with sketches of experienced structural failures and proposed repairs

- documentation required for survey, including supporting documents

- the guidance of the Tanker Structure Co-operative Forum (see Appendix I for further details of the Forum) in areas of corrosion, defects and repairs, ultrasonic gauging and the strength of corroded structural items, as well as corrosion and maintenance evaluation of tanker structures.