Stud Link vs. Studless Anchor Chain: Which to Choose?
When selecting anchor chains, the distinction between stud link and studless is the most fundamental structural classification. Many purchasers focus solely on the presence or absence of the cross-stud, overlooking the underlying differences in working load capacity and grade selection. This article clarifies the key information needed to make the right choice.
I. Structural Differences: The Role of the Stud
Stud link anchor chains feature a cross-stud in the center of each link. This stud prevents the link from deforming under load, maintains the link's shape, and reduces kinking and tangling.
Stud link chains, by contrast, are more rigid and resist twisting and kinking better.
Studless anchor chains lack this cross-stud, resulting in a simpler structure and greater flexibility.
II. Weight Differences: Not the Deciding Factor
For the same specifications, stud link chains are slightly heavier than studless chains. While the stud itself adds only a small amount of metal volume, the weight difference primarily stems from slight adjustments to the link's cross-section required to accommodate the welded stud. The exact weight difference varies by specification and manufacturing standard; actual factory specification sheets should be consulted for precise figures.
When selecting a chain, working load capacity is the primary criterion, while weight is secondary.
III. Working Load Differences: Stud Link Is Approximately 1.5 Times Studless
The difference in working load (proof load) is more significant than the difference in weight. According to GB/T 549-2017 and actual factory data:
- 12.5mm: Studless 41.2 kN, Stud Link 66 kN
- 28mm: Studless 203 kN, Stud Link 321 kN
- 56mm: Studless 802 kN, Stud Link 1,220 kN
The Pattern: The working load of a stud link anchor chain is approximately 1.5 to 1.6 times that of a studless chain. While the ratio decreases slightly as the chain diameter increases, it remains consistently around 65%.
Why is the difference so significant? The stud in a stud link chain enhances the link's resistance to deformation, resulting in a breaking load approximately 20% higher than that of a studless chain of the same specification. Since the ratio of breaking load to proof load (approximately 1.4) is the same for both types, the difference in breaking load is reflected proportionally in the working load limit.
IV. Choosing the Grade: AM2 vs. AM3
According to GB/T 549-2017, stud-link anchor chains are classified into grades AM1, AM2, and AM3, while studless anchor chains fall into grades BM1, BM2, and BM3. Currently, AM1 and BM1 grades have been largely phased out; the mainstream options on the market are AM2/AM3 and BM2/BM3.
In terms of supply, AM2 starts at a diameter of 12.5 mm, while AM3 starts at 20.5 mm; AM3 anchor chain accessories generally begin at 56 mm. At SMEOCEAN, we can accommodate custom orders for small-specification AM3 accessories.
What about the price difference?
For the same specifications, AM3 is approximately 20%–40% more expensive than AM2. This higher cost is due to the materials used (CM690 alloy steel vs. CM490 carbon-manganese steel), the heat treatment process (quenching and tempering vs. normalizing), and the addition of the stud and associated manufacturing steps. While the chain link body is formed from a single rod cut, heated, bent, and flash-welded, the stud is a separate forged component that must be pressed into the link and secured by welding. For AM3, the stud requires reinforcement welding, and there are strict requirements regarding the weld location—it must be welded on the side opposite the flash weld to prevent heat accumulation and resulting stress concentration. In contrast, AM2 studs are primarily press-fitted; some standards allow for no welding or only simple tack welding.
For detailed specifications, weights, and certification information regarding AM2 and AM3, please refer to our Anchor Chain Product Catalog to download the full specification sheet.
V. A Common Selection Error
Some purchasers focus solely on weight and unit price, opting for studless chains because they are lighter and cheaper. However, for the same nominal size, the working load limit of a studless chain is only about 1/1.55 that of a stud-link chain. If your windlass, chain stopper, or chain locker was designed based on the working load of stud-link chains, switching to studless chain could result in a system mismatch.
When selecting a chain, working load should be the primary criterion; weight and price are secondary.
VI. Quick Selection Guide
- Large commercial vessels, offshore platforms, or harsh anchoring environments with high loads → Choose stud-link chain.
- Small vessels, fishing boats, inland waterway vessels, or relatively calm anchoring environments with low loads → Studless chain is sufficient.
- Chain diameter ≤17mm and permitted by regulations → Studless chain can replace stud-link chain.
- Uncertain? → Tell us your vessel type, chain diameter, and anchoring environment, and we will help you decide.
Not sure whether to choose AM2 or AM3? Contact our engineers with your vessel type, chain diameter, and anchoring environment, and we will provide a recommendation.
VII. Why Norway and Chile Choose Different Chains
Despite both engaging in auqaculture salmon farming, Norwegian farms generally use stud-link anchor chains, whereas Chilean farms predominantly use studless anchor chains. This is not a matter of preference; it is determined by marine environmental conditions.
Norwegian waters feature strong winds and waves, deep water, and high current speeds, subjecting farming cages to extreme loads; the higher working load and superior deformation resistance of stud-link chain are essential requirements. In contrast, Chilean farming waters are relatively calm and shallow, making the flexibility and lighter weight of studless chain better suited for frequent handling and installation.
The core of selection is never "which is better," but rather "which is more suitable for your specific waters."
We can provide a tailored technical analysis based on your farming site conditions—water depth, wind and wave conditions, current speed, and seabed composition—to help you decide between stud-link and studless, or AM2 and AM3.
More Links：
CM690 76mm Stud Link Anchor Chain – Manufacturing Process
27.5-Meter Anchor Chain for 10,000-Ton Ships
What are Anchor Chains Used for?