The International Association of Classification Societies (IACS) has published a new Uniform Requirement UR M85, providing the marine industry with the first comprehensive technical guidance for type approval testing of synthetic materials used in stern propeller shaft bearings.
These bearings are considered critical components of a ship's propulsion system and are essential to the safety and efficiency of long-term operations. The new UR M85 establishes a robust framework for type approval testing to address an important gap in maritime standards. Its key elements include:
Type Approval Testing Requirements: A structured, detailed test plan must be developed, including a comprehensive description of each product, precise selection of test specimens, and specific test conditions. This framework ensures alignment with industry standards, providing consistency and clarity for manufacturers.
Material Property Compliance: Non-elastic and elastomeric materials used for stern propeller shaft bearings must meet stringent performance benchmarks, including tensile strength, elongation, and metal adhesion. These properties are critical to maintaining the structural integrity and performance of the entire bearing under a variety of operating conditions, and are therefore detailed in the relevant UR tables.
Approved Testing Facilities: Type approval testing must be conducted in laboratories accredited to ISO/IEC 17025. This standardization ensures that material property testing is reliable, accurate, and conducted with the highest quality, reinforcing IACS's commitment to strict compliance with the rules.
Wear Testing Procedures: To assess the durability of materials, wear testing must comply with ASTM G77-17 or equivalent standards and specify strict parameters for shaft material, lubrication type, and test duration. These guidelines ensure consistent and reliable wear data, reducing variability and supporting predictable product performance.
Environmental Conditions for Testing: Testing must be conducted under strictly controlled environmental conditions, including regulation of temperature, humidity, and the use of surrogate seawater. By simulating operating conditions, UR ensures that materials are thoroughly tested for real-world application suitability and resilience, thereby improving overall safety.
Type Approval Certificate Issuance: Upon successful completion of testing and submission of technical documentation, the Classification Society will issue a Type Approval Certificate. This certificate is a sign of product quality and compliance with IACS standards, providing confidence to shipowners and operators.
