Anchor Chain

Marine stud Link anchor chain is a special chain that connects the anchor and the ship. Due to its own heavy weight, the marine stud Link anchor chain can buffer external forces when yacht or boat moored in the water. The marine anchor chain in the water not only keep the anchor level, but also favor the anchor firmly grasp the bottom.

An marine stud Link anchor chain is often composed of anchor end links, intermediate links, and end links. According to the structure of the chain link, it can be divided into two types such as a stud link chain and studless link chain. The stud link chain is stronger than the studless one.

Marine stud link anchor chain has less deformation, and is not easy to twist when stock. It is widely used by large and medium-sized ships boat anchor parts. The studless link anchor chain is only used for small ships. When diameter of the anchor chain are required not exceed 17mm, operator can use a studless anchor chain with same test load, or a steel wire or fiber rope with the same breaking load for same purpose.

The weight of the anchor chain is negligible for the boat, and its friction will not play a big role. Generally speaking, when the ship is anchored, the anchor chain is straight, and the effect of friction can basically be ignored.

From the top of the ship, the anchor chain is straight, but under the water there is a part that is parallel with the seabed, but it is actually close to the seabed. The anchor provides the grip, and then transmits the force to the ship through the anchor chain to withstand the influence of the external load of the ocean flow, wind and waves on the positioning. This part close to the seabed which aims to take the the influence of the force into consideration.

Types of Anchor Chain

Testing Of Finished Anchor Chains

Tests shall be carried out in accordance with the requirements and standards of the Code for tension and breakage. Below are common tests for anchor chains.

a. Tensile test:

A tensile test is performed on each link of the entire chain. Each section of anchor chain is to be subjected to a tensile load test on an approved testing machine according to the corresponding grade of anchor chain. During the test, the relative position of each chain link shall be correct, and the entire chain shall not be twisted. After the load has been removed, each section of the chain, including its dimensions, is to be inspected and there should be no obvious defects. Chainrings and accessories should be carefully checked for appearance, size and relative rotational flexibility, and permanent elongation should not exceed 5% of their original length.

b. Pull-off test:

According to the specified number of samples, select an anchor chain from every four sections of anchor chain. For AM2 and AM3 anchor chains, every 4 sections of welded anchor chain should be used as a batch, and each batch should not be more than 4 sections of anchor chain. Cut samples with no less than 3 links, and conduct the test according to the breaking load specified in the specification. The test links shall be made in the same manufacturing process as the anchor chain, welded and heat treated together with the anchor chain. The test links are to be removed from the anchor chain in the presence of the Surveyor.

The test specimen is considered to have passed the test if the specimen does not break when the specified load is applied. If the tensile test does not meet the requirements, two more samples can be taken from the same anchor chain for the test. If the requirements are met, the test is considered qualified. If the re-examination is still unqualified, the anchor chain of this section shall be judged as unqualified. However, according to the requirements of the manufacturer, the other three anchor chains can be subjected to tensile breaking tests respectively. If one of the test results does not meet the requirements, all three anchor chains are unqualified.

If the mechanical properties of the chain link are unqualified, re-sampling can be performed after heat treatment. After a retest, if it is still unqualified, the anchor chain of this section shall be judged as unqualified.

The anchor chain accessories should generally be subjected to tensile test and tensile test according to relevant regulations, except those approved by the classification society to be exempted from the test, and the accessories that have undergone the tensile test are generally not allowed to be reused.

After the anchor chain test is qualified, both ends of each anchor chain shall be marked with steel stamps such as the anchor chain grade, certificate number and the logo of the classification society.