Overview
ISO 24059:2021 - Ships and marine technology - Anchor chain releasers - is an international standard that defines the classification, structure, basic dimensions, material and performance requirements, test methods, and marking/surface signs for anchor chain releasers. Applicable to the design, production and acceptance of anchor chain releasers, this standard supports safe anchoring arrangements on ships and offshore units.
Key SEO phrases: ISO 24059:2021, anchor chain releasers, ships and marine technology, anchor chain standard.
Key topics and technical requirements
- Classification and types: Specifies three types of anchor chain releasers (Type A - tongue; Type B - plug; Type C - plug with butterfly nuts) and their nominal size ranges (Type A: 36–152 mm; Types B & C: 50–120 mm). Type selection guidance includes application and locking method constraints (e.g., restrictions on Type C where PSC forbids butterfly nuts).
- Structure and dimensions: Detailed component definitions and main dimensions are provided for each type, with illustrative figures and tables to support manufacturing and inspection.
- Materials: Minimum mechanical properties are specified for major components (e.g., hull steel and carbon steels with specified minimum yield stresses). Packing and gasket materials: polychloroprene, Shore hardness 35–45, tensile strength ≥ 14 MPa.
- Surface treatment and derusting: Surface cleanliness to be at least Sa2.5 or St3 per ISO 8501-1; two coats of anti-rust primer and lubrication of shafts required.
- Strength and performance:
- No chain breakaway under 15% of the anchor chain breaking load (see ISO 1704 for chain breaking load).
- Automatic release via controlled cracking between 15% and 30% of chain breaking load.
- Strength calculations for hooks, plugs and pins referenced in Annex A.
- Tightness and watertightness: Requires water pressure testing above design pressure and onboard watertight test with no external leakage.
- Dimensional tolerances & testing: Unspecified tolerances follow ISO 2768-1 (class C). Test methods cover material certification, visual inspection, operational cycling (≥3 starts for moving parts), derusting inspection, dimensional checks and strength/tightness testing.
- Marking & signs: Requirements for marking and surface signs to support identification and safe operation.
Applications and users
- Shipbuilders and marine equipment manufacturers - for design and production of anchor chain releasers.
- Classification societies and inspection bodies - for acceptance testing and certification.
- Shipowners, marine engineers and ship repair yards - for procurement, installation and maintenance.
- Port State Control and flag administrations - for compliance checks where releaser design affects safety and PSC acceptance.
Related standards
ISO 24059:2021 is essential for ensuring consistent, tested, and clearly marked anchor chain releasers that meet international safety and performance expectations.