Shipbuilding and Repair Quality Standard (IACS Rec 47)

Author: IACS

Published: JUNE 2025

This publication provides guidance on shipbuilding quality standards for hull structures during new construction and offers remedial criteria where these standards are not met. Applicable to conventional merchant ship types and structures fabricated from normal and higher strength steels, it outlines the acceptable workmanship ranges and inspection tolerances that support consistent and safe construction practices. It is intended for use where no established national or shipbuilding standards have been adopted by the Classification Society.

This standard sets out shipbuilding quality requirements for hull structures during new construction, including criteria for corrective measures when those requirements are not achieved. It also includes repair quality standards for existing ships. This standard is intended for situations where no recognised shipbuilding or national standards are in place.

Although the standard generally applies to conventional merchant vessels, hull areas governed by the rules of the Classification Society and hull structures constructed from normal and higher strength hull structural steel, applicability is subject to agreement with the Classification Society.

It does not typically apply to special ship types, such as gas tankers, or to structures made from stainless or other special steels.

The standard defines both 'Standard' and 'Limit' ranges for workmanship. The 'Standard' range reflects expected outcomes under normal conditions, while the 'Limit' range indicates the maximum allowable deviation. Work falling within the 'Limit' range is considered acceptable; where no such limit is given, values beyond the 'Standard' may still be accepted by the Classification Society.

It includes requirements for general construction practices, gas cutting, fabrication, alignment, welding joint details and remedial actions. Separate provisions cover repairs, including general repair requirements, welding, material use and qualification of personnel involved in repair work.

For any structural details or fabrication procedures not included in the standard, Classification Society approval is required based on qualified procedures or recognised national standards. The standard also specifies qualification requirements for personnel and procedures and includes dedicated guidance on the use of materials.

Table of Contents:

References
Standards
- PART A Shipbuilding and Remedial Quality Standards for New Construction
1. Scope
2. General requirements for new construction
3. Qualification of personnel and procedures
4. Materials
5. Gas Cutting
6. Fabrication and fairness
7. Alignment
8. Welding Joint Details
9. Remedial
- PART B Shipbuilding and Repair Quality Standard for Existing Ships
References
Standards
1. Scope
2. General requirements for repairs and repairers
3. Qualification of personnel
4. Materials
5. General requirements to welding
6. Repair quality standard