What Is a Chafe Chain? | SPM Single Point Mooring Systems
In Single Point Mooring (SPM) operations, a million-dollar synthetic fiber mainline can be instantly rendered unusable due to friction from the hull's edge. The chafe chain, located at the end of the mooring line, is the first line of defense protecting this "lifeline at sea."
A chafe chain (also called a friction chain) is a short steel chain assembly installed at the end of a synthetic fiber mooring line, passing through the ship's guide wires and connecting to the hull structure. Chafe chains are designed for dynamic friction protection during SPM operations and are not suitable for long-term static mooring.
Core Functions
- Sacrificial Protection: Protects the synthetic mainline from cuts and abrasion by using steel chain links to withstand friction and bending at the guide.
- Force Transfer: Transfers mooring loads from the flexible cable to the hull's hard points.
- Emergency Protection: Provides additional mechanical strength buffer in the event of accidental overload of the mainline.
Technical Specifications and Configuration
- Length: Standard configuration approximately 11 meters (OCIMF MEG4 recommended, suitable for mostVLCCs), customizable from 8-13 meters depending on the vessel's depth.
- Structural Composition: End Link/Enlarged Link + 27 Common Links + Connecting Shackles
- Connection Method: One end connects to the synthetic cable via a pear-shaped link or shackle; the other end connects to the hull structure via a combination of swivel and shackle.
- Quantity: Depends on vessel tonnage and SPM system requirements; for large tankers (≥150,000 tons). DWT (Dry Wt) tankers are typically required in pairs.
Material Grades and Specifications
We offer dual-track material options to meet different project standards:
1. R3 (yield strength 690MPa, tensile strength 770MPa) and R4 (yield strength 770MPa, tensile strength 860MPa), conforming to IACS W22 and OCIMF MEG4 standards, suitable for international tanker projects, operations in harsh sea states, or deep-water operations.
2. Grade 3 (M690, yield strength 690 MPa), conforming to classification society material certification specifications, suitable for coastal operations and specific customer technical agreement projects. 3. Standard Specifications: Ø54mm, Ø64mm, Ø76mm, Ø84mm (Other specifications can be customized)
Professional Tip: Although IACS W22 recommends R3/R4 mooring chain grades, in non-extreme sea states or projects with specific technical agreements, Grade 3/M690 material can also be a cost-effective and reliable alternative after case-by-case approval by the classification society. We can provide optimal material recommendations based on your project's Technical Specifications (ITTs).
FAQ
Q1: Can Grade 3 M690 Chafe Chains be used for international projects?
A: It depends on the project's Technical Specifications (ITTs). Some projects accept Grade 3 material certified by the classification society, but high-end projects strictly adhering to OCIMF MEG4 typically require R3/R4. We recommend confirming the end customer's technical agreement in advance.
Q2: Can the standard length of the Chafe Chains be adjusted?
A: Yes. While 11 meters (36 feet) is the standard length recommended by OCIMF (suitable for the molded depth of most tankers), we can customize the length according to the specific guide height and freeboard of the vessel.
Q3: Does the chafe chains need to be replaced periodically?
A: Yes. As a "sacrificial" component, the chafe chain is allowed to wear during its service life, but the wear on the chain links must be checked periodically. According to IACS Rec.10 and classification society regulations, when the chain link diameter decreases by more than 5% of its original diameter due to wear, or when cracks or deformation appear, it must be replaced immediately.
Q4: Do you provide complete SPM mooring equipment?
A: We specialize in manufacturing chafe chains and connectors, and can work with customers' mooring cable suppliers to provide complete force transmission path components from cable to hull connection.
Conclusion: SMEOCEAN is a professional manufacturer of marine anchor chains, mooring chains, and chafe chains, with products widely used in SPM single-point mooring, dock mooring, and other offshore mooring systems.
In the SPM mooring system, the Chafe Chain is a crucial detail. Whether for deep-sea projects requiring high-grade R4 mooring chains or for near-shore operations seeking cost-effective Grade 3 solutions, SMEOCEAN can provide you with the best solutions and products.
Contact us for technical specifications or a quote: As a professional marine anchor chain manufacturer, we look forward to safeguarding your mooring safety at sea with products that meet international standards.
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