Guidance Manual for Tanker Structures: 2025 [paper]

Guidance Manual for Tanker Structures (GMTS) – Consolidated Edition 2025-26

This consolidated edition combines various sources of information on surveys, maintenance and repairs of tanker structures into one guidance manual. This information is necessary for assessing and monitoring the condition of in-service ballast tanks, cargo tanks and other tanker structures.

While the original manual primarily addressed the conventional single hull tanker, this revised edition includes ‘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. The guidance also includes updated information on safety and access during surveys, including the updated ‘IACS Recommendation No. 72: Confined Space Safe Practice Rev.4’ (Jan 2025).

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.

The guidance manual provides comprehensive guidance and information on IACS and owner’s surveys, as well as on technical maintenance and repair. It includes guidance on structural defects, corrosion in tank spaces, fatigue and other survey procedures such as thickness measurement, which is important in monitoring.

Guidance Manual for Tanker Structures – Consolidated Edition 2025-26, BP109803