Anchor chain refers to a special chain that connects the anchor and the hull and transmits the anchor’s holding power. It is often composed of anchor end links, intermediate links and end links. Each chain link is connected to the adjacent chain link, and finally forms a chain of any specified length.
Types of Anchor Chains
1. Classification by the link structure: Stud Link Chain, Studless Chain.
- The chain link of a stud link chain is equipped with crosspieces. When the size and material are the same, the strength of the stud link chain is greater than that of the studless chain, the deformation is small, and it is not easy to twist when stacked. And it is widely used for modern large and medium-sized ships.
- The chain link of a studless anchor chain has no crosspieces and is only used for small ships. The specification stipulates that when the diameter of the anchor chain equipped as required does not exceed 17mm, it can be replaced by a studless anchor chain with the same test load, or a steel wire or fiber rope with the same breaking load.
2. Classification by the manufacturing method: cast steel anchor chain, flash welded anchor chain, and forged anchor chain.
- The cast steel anchor chain has high strength, good rigidity, small deformation, wear resistance, the crosspiece is not easy to lose, and the service life is long. And it is suitable for large-scale production. The disadvantage is that the process is complicated, the cost is high, and the impact resistance is poor.
- The electric welded anchor chain is bent and welded with round steel materials that meet the requirements. It has the advantages of advanced and simple production technology, low cost, and good quality.
- Forged anchor chain has good impact resistance and toughness, but the manufacturing process is complicated, the cost is high, and the quality is unstable.
At present, electric welded anchor chains have been most widely used on merchant ships. Almost all anchor chains are manufactured by flash welding, and cast anchor chains are rarely used. Except that most of the anchor chain accessories are forged parts, forged anchor chains have basically been eliminated.
3. Classification by the purpose: marine anchor chain and mooring anchor chain.
4. Classification by the steel grade: marine anchor chains are divided into AM1, AM2, and AM3, and mooring anchor chains are divided into R3, R3S, R4, R4S, R5.
Anchor Chain Parts Definition and Chain Fittings
A complete anchor chain first consists of many anchor chain links connected to each other to form an anchor chain link of a certain length, and then several anchor chain links are connected by connecting links or connecting shackles to form the entire anchor chain.
The definitions of the stud-link anchor chains component parts:
Chain-shot
Component of an anchor chain consisting of common stud links and joining shackles with a given nominal length (27.5m or 25m) in accordance with ISO 3828
Common stud link
Basic link of which chain-shot consists.
Enlarged stud link
Strengthened link that connects a common stud link and the end link, in the case of connecting chain-shots, with a “D” type joining shackle, or connects a common stud link and swivel.
End link
Strengthened link that is attached to the ends of chain shots, in the case of connecting chain shots, with “D” type joining shackles or the outboard chain shot with an end shackle.
Joining shackle
“D” type joining shackle or Kenter type joining shackle used for connecting chain shots.
End shackle
Enlarged shackle used for connection of the outboard chain shot to the anchor.
Swivel
Movable component of the outboard chain shot which prevents excessive twisting of the chain cable.
Outboard chain-shot
Additional short chain-shot fastened to the anchor shackle.
Nominal size
Nominal diameter of the common stud link.
Anchor Chain Fittings:
Pear Shackle, Kenter Shackle, Anchor End Shackle and Swivel Forerunner.
The Function of Anchor Chains
The main function of the anchor chains is to fix and stabilize the ship. The main is about the following 3 aspects:
- For the anchor chain to work, the most basic condition is to hook things on the seabed. If the anchor chain is not long enough, the anchor will not work. If the seabed is flat, or the thing the anchor is hooked on is not fixed, or the hook is not too strong, if it is calm and the waves are still okay. Once the waves are too big, the anchor will not be able to hook things, and the anchor will lose its function. This is called “anchor moving”. It is very dangerous for the ship to move the anchor during the anchoring period. Because the main engine usually stops when the ship is anchored. If the ship is driven immediately, it will take time. It is very dangerous for an unpowered boat to float around. Therefore, the concept of anchorages came into being. Anchorages, in other words, are rougher under the sea, and in addition, they must be sheltered from the wind.
- The weight of the anchor chain is negligible for the ship, and that little friction will not play a big role. Generally speaking, when the ship is anchored, the anchor chain is straight, which is basically negligible friction. If you are by the sea, you will find many small fishing boats whose anchor chains are thick ropes.
- When viewed on the ship, the anchor chain is straight, but there is a section under the water that is close to parallel to the seabed (in fact, it is close to the seabed). The anchor provides the holding power, which is then transmitted to the ship through the anchor chain to resist the influence of the external load of the sea currents and wind waves on the positioning. The reason why there is a section close to the seabed is to consider the influence of the force. Think about it, the anchor, anchor chain is easy to move when pulled straight. And there is a section close to the seabed, which can provide a margin within a certain range.
Summary
Anchor chain is an indispensable part of marine equipment. It can keep your boat stable at all times, so as to avoid damage caused by wind and waves. As a leading marine equipment supplier, Boomarine provides studless chains and stud link chains painted with black paint or HDG. And it has all classification certificates such as ABS, BV, DNV, LR, etc. In addition, Boomarine also provides marine anchors, marine fenders, and other deck equipment for you to choose from. We can provide you with integrated and customized solutions. Feel free to contact us at any time.
