Overview
ISO 1704:2022 - "Ships and marine technology - Stud-link anchor chains" defines the shape, proportions, dimensions and tolerances for stud-link anchor chains and their component parts. The fourth edition updates chain grades, dimensional tolerances, joining and swivel shackle types, and adds guidance on material requirements, loading methods (proof/breaking loads) and marking. Note: statutory and class requirements for individual ships can also apply.
Key topics and technical requirements
- Scope and model geometry: Standard shapes and proportions are illustrated in the standard model figures (links, shackles, swivels). Nominal dimensions are provided in tabular form and are the basis for manufacture and inspection.
- Nominal size relationships: Enlarged links are specified as 10% larger (d = 1.1·d) than common links; end links are 20% larger (d = 1.2·d).
- Taper pins: Retaining pins for D‑type and Kenter shackles are defined by taper ranges:
- D‑type: taper between 1:50 and 1:16 on diameter
- Kenter type: taper between 1:50 and 1:32; nominal pin diameter = 0.37 × d
Pins must conform to ISO 2339 dimensions and permitted materials/coatings (stainless or tin‑coated carbon steel per ISO 2093 where applicable).
- Tolerances and measurement: Manufacturing tolerances for link diameters, lengths (e.g., length of five links), flush‑butt welds and other dimensions are specified. Critical dimensional measurements are taken after statutory proof‑load treatment (see Clause 4.2.1.3).
- Grades and mechanical properties: Anchor chain grades (1–4) are defined; Grade 4 is newly specified with higher strength and mechanical property requirements (see Clause 9).
- Connections and component specifications: Detailed nominal dimensions and shapes for common links, enlarged links, end links, D and Kenter joining shackles, end shackles, swivels and swivel shackles (Type A/B) are provided (Clauses 7.2–7.10).
- Testing and marking: Requirements for breaking load tests, proof loads, test conditions, and mandatory marking positions/information are included (Clauses 10–11).
Practical applications
- Procurement and specification of marine anchor chains for merchant and offshore vessels
- Production design and quality control for chain manufacturers and shackle suppliers
- Inspection, certification and survey work performed by class societies, shipyards and maritime inspectors
- Installation, maintenance and replacement planning for ship operators and rigging crews
- Ensuring compatibility in chain‑shot assemblies, joining shackles and outboard chain‑shot connections
Who should use ISO 1704:2022
- Shipbuilders, naval architects and marine engineers
- Anchor chain and rigging manufacturers
- Classification societies, port state control and maritime regulators
- Marine procurement specialists and ship operators
- Surveyors and inspection authorities
Related standards
- ISO 2339 - Taper pins, unhardened (referenced for taper‑pin dimensions)
- ISO 2093 - Electroplated coatings of tin (referenced for tin coating requirements)
Keywords: ISO 1704:2022, stud-link anchor chains, anchor chain dimensions, chain tolerances, chain grades, joining shackle, Kenter shackle, taper pin, breaking load, proof load, marine chains.
