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What Size is an Anchor Chain? A Complete Guide to Sizing, Standards & Applications
Anchor chain size is the foundational parameter that determines the safety, durability, and suitability of mooring systems for vessels, offshore platforms, and marine engineering projects. Unlike general industrial chains, anchor chain sizing follows strict international marine standards, with dimensions directly matched to the working load, environmental conditions, and equipment tonnage.
The primary indicator of anchor chain size is the nominal diameter of the chain link bar (d), measured at the thickest point of the straight section of the chain link, excluding weld flashes or surface coatings. This standard is uniformly adopted by all major classification societies (CCS, ABS, DNV, LR, BV) to ensure cross-compatibility between chains, anchors, and windlass equipment.
In addition to diameter, anchor chain sizing also includes three key dimensional parameters:
Link length (L): Standardized as 6 × nominal diameter (6d) for most marine applications
Link width (W): Standardized as 3.6 × nominal diameter (3.6d)
Section length: Standard 27.5m (90ft) per shot for most markets, with 25m and 15-fathom (27.43m) options available for regional requirements
Anchor chains are categorized into four main product lines, each with distinct size ranges tailored to specific use cases:
Designed for small yachts, fishing boats, workboats, and coastal vessels under 500 GT:
Diameter Range | Typical Application | Recommended Grade | Standard Length Options |
|---|---|---|---|
10mm – 16mm | <10m yachts, small fishing boats | Grade 2, Grade 3 | 27.5m, 50m, 100m |
18mm – 28mm | 10m – 24m workboats, coastal cargo vessels | Grade 3, R3 | 27.5m, 110m, 150m |
Used for bulk carriers, container ships, oil tankers, and general cargo vessels from 500 GT to 300,000 GT:
Diameter Range | Vessel Tonnage | Common Grade | Classification Society Certification |
|---|---|---|---|
28mm – 50mm | 500 – 10,000 GT | R3, R3S | CCS, ABS, BV |
52mm – 80mm | 10,000 – 100,000 GT | R4, R4S | DNV, LR, NK |
82mm – 100mm | 100,000 – 300,000 GT | R5 | All major societies |
Engineered for floating production storage and offloading (FPSO) units, semi-submersible drilling platforms, offshore wind turbines, and deep-sea mooring systems:
Diameter Range | Application | Special Performance Requirements |
|---|---|---|
50mm – 120mm | Offshore wind turbines, shallow water platforms | Corrosion resistance, fatigue life >25 years |
122mm – 180mm | FPSOs, mid-depth drilling platforms | High tensile strength, low temperature impact resistance (-40°C) |
182mm – 208mm | Ultra-deepwater mooring systems (1500m+ depth) | R6 grade, minimum breaking load >20,000 kN |
For non-standard use cases including aquaculture mooring, underwater engineering, and specialized marine equipment, we offer custom sizing from 6mm up to 220mm diameter, with custom section lengths, surface treatments, and strength grades to match your exact project requirements.
All data below complies with ISO 1704:2022 marine standards and is certified by major classification societies (ABS, DNV, LR, CCS, BV). All parameters are for stud link anchor chains; studless chain parameters are available upon request.
For yachts, small fishing boats, workboats under 500 GT, and coastal mooring applications.
Nominal Diameter (mm) | Weight per Meter (kg/m) | Grade 2 Minimum Breaking Load (kN) | Grade 3 Minimum Breaking Load (kN) | Typical Application |
|---|---|---|---|---|
10 | 1.8 | 50 | 70 | <8m small yachts, dinghies |
12 | 2.6 | 72 | 92 | 8m–10m coastal yachts |
14 | 3.5 | 100 | 116 | 10m–12m recreational vessels |
16 | 4.6 | 129 | 150 | 12m–15m offshore yachts |
18 | 5.8 | 162 | 188 | 15m–18m workboats |
20 | 7.2 | 200 | 234 | 18m–22m coastal fishing boats |
22 | 8.7 | 242 | 285 | 22m–26m small cargo vessels |
24 | 10.3 | 288 | 340 | 26m–30m workboats |
26 | 12.1 | 338 | 400 | 30m–35m coastal vessels |
28 | 14.0 | 392 | 465 | 35m–40m commercial vessels under 500 GT |
For bulk carriers, container ships, oil tankers, and general cargo vessels from 500 GT to 300,000 GT, complying with IMO A.761(18) mooring requirements.
Nominal Diameter (mm) | Weight per Meter (kg/m) | R3 Minimum Breaking Load (kN) | R3S Minimum Breaking Load (kN) | Typical Vessel Tonnage |
|---|---|---|---|---|
30 | 16.1 | 522 | 600 | 500–1,000 GT |
36 | 23.2 | 750 | 870 | 1,000–3,000 GT |
40 | 28.6 | 928 | 1,080 | 3,000–5,000 GT |
46 | 37.8 | 1,230 | 1,430 | 5,000–10,000 GT |
50 | 44.7 | 1,450 | 1,690 | 10,000–20,000 GT |
56 | 56.1 | 1,820 | 2,120 | 20,000–40,000 GT |
64 | 73.2 | 2,380 | 2,770 | 40,000–70,000 GT |
73 | 95.5 | 3,100 | 3,610 | 70,000–120,000 GT |
81 | 117.5 | 3,820 | 4,450 | 120,000–200,000 GT |
90 | 145.0 | 4,700 | 5,480 | 200,000–300,000 GT |
100 | 179.0 | 5,800 | 6,760 | 300,000 GT+ ultra-large vessels |
For offshore wind turbines, FPSOs, semi-submersible drilling platforms, and deep-sea mooring systems, with design life up to 30 years.
Nominal Diameter (mm) | Weight per Meter (kg/m) | R4 MBL (kN) | R4S MBL (kN) | R5 MBL (kN) | R6 MBL (kN) | Typical Application |
|---|---|---|---|---|---|---|
50 | 44.7 | 1,810 | 1,990 | 2,180 | 2,550 | Shallow water offshore wind turbines (<30m depth) |
76 | 103.5 | 4,180 | 4,590 | 5,030 | 5,890 | Mid-depth offshore wind turbines (30–60m depth) |
90 | 145.0 | 5,870 | 6,450 | 7,070 | 8,270 | 10MW+ floating wind turbines |
114 | 233.0 | 9,420 | 10,360 | 11,350 | 13,270 | FPSOs, shallow water drilling platforms (<500m depth) |
137 | 336.0 | 13,600 | 14,950 | 16,380 | 19,150 | Mid-depth drilling platforms (500–1,500m depth) |
157 | 441.0 | 17,850 | 19,630 | 21,510 | 25,140 | Deepwater drilling platforms (1,500–2,500m depth) |
178 | 566.0 | 22,900 | 25,200 | 27,600 | 32,200 | Ultra-deepwater mooring systems (>2,500m depth) |
208 | 773.0 | 31,300 | 34,400 | 37,700 | 44,000 | Special deep-sea engineering projects |
Choosing the wrong anchor chain size can lead to catastrophic mooring failure, equipment damage, and safety risks. Follow this 4-step selection process:
Calculate the maximum environmental load your system will experience, including wind, wave, and current forces. Your anchor chain's minimum breaking load (MBL) should be at least 3 times the maximum working load (safety factor of 3:1 for static mooring, 5:1 for dynamic offshore applications).
Higher strength grades allow smaller diameter chains to achieve the same breaking load as larger lower-grade chains. For example, a 60mm R5 chain has equivalent MBL to a 76mm R3 chain, reducing overall system weight by 35% for deepwater applications.
Ensure your selected chain size matches the specifications of your anchor, windlass, chain stopper, and other mooring system components. Mismatched sizing can cause excessive wear, jamming, and equipment failure.
All anchor chains used in commercial marine or offshore applications must carry valid certification from the appropriate classification society for your operating region. Our technical team provides free compliance verification for all anchor chain products we supply.
Oversizing for cost savings: While lower-grade, larger-diameter chains may have lower upfront cost, they add significant weight, increase windlass load, and reduce overall system efficiency.
Ignoring wear allowance: For long-term mooring applications, specify a chain diameter 2–3mm larger than the minimum required to account for corrosion and wear over the service life.
Using non-calibrated chain: Only calibrated anchor chains are compatible with standard windlass equipment. Non-calibrated chain will slip, jam, and cause premature equipment failure.
At JN Anchor Chain, we manufacture and supply the full range of anchor chain sizes from 6mm to 208mm, with all products certified by CCS, ABS, DNV, LR, BV, and other major classification societies. Our in-house testing facility ensures every meter of chain meets or exceeds international standards, with custom sizing available for specialized projects.
To request a quote for your specific anchor chain size requirement, or to speak with our technical team for sizing assistance, contact us today.
