Marking Methods for Marine Anchor Chains

A ship’s anchor chain marking refers to the markings painted on the connecting links (or connecting shackles) and the adjacent links, which indicate the segments of the ship’s anchor chain. These markings help crew members promptly determine when the ship is anchoring or weighing anchor and keep track of the length of the anchor chain being deployed. Probably most people aren’t very familiar with them—so let’s take a closer look at how these markings are made.

What are the specific criteria for equipping marine anchors and anchor chains?

When using ships, we naturally think of anchor chains and anchors. To ensure a reliable offshore experience, however, we also need to acquire some specialized knowledge. Currently, welded anchor chains are widely used in commercial vessels. Almost all anchor chains are manufactured by flash welding, while cast anchor chains are rarely employed. With the exception of most forged components found in anchor chain fittings, forged anchor chains have largely been phased out. So, what kind of anchor chains and anchor assemblies should be equipped on seagoing vessels?

The principle, function, types, and daily inspection of ship anchors

The structure of a ship’s anchor, from top to bottom, consists of the anchor shackle, bolt, anchor rod, anchor stock, and anchor arm. The symmetrical parts on either side are called anchor flukes. The anchor flukes are the most critical component for the anchor to grip into the seabed. After a ship drops anchor, the anchor sinks to the seabed under the pull of the anchor chain. Once at the seabed, thanks to the action of the anchor rod, the plane where the anchor arm lies becomes perpendicular to the seabed, at which point the anchor flukes come into contact with the seafloor. Typically, the length of a ship’s anchor chain exceeds the water depth; therefore, the portion of the anchor chain lying on the seabed remains flat. When the ship experiences disturbances—such as when encountering head seas—the anchor chain gets pulled, and the anchor resting on the seabed, at the point where it’s connected to the chain, is subjected to a horizontal force. At the same time, the ship...

What is the function of a ship's anchor?

The primary function of a ship’s anchor is to secure and stabilize the vessel. This can be explained from the following aspects: 1. For an anchor to work effectively, the most fundamental requirement is that it must hook onto something on the seabed. If the anchor chain isn’t long enough, the anchor won’t be able to do its job. If the seabed is flat, or if the object the anchor is hooked onto isn’t firmly fixed, or if the hook isn’t secure enough, then while the sea may be calm, once the waves become too high and the anchor can no longer hold onto anything, the anchor will lose its effectiveness. This phenomenon is called “anchor dragging.” During anchoring, if the ship experiences anchor dragging, it becomes extremely dangerous.

Working principle of a ship anchor

From top to bottom, the structure consists of an anchor shackle, bolts, an anchor rod, an anchor stock, and an anchor arm. The symmetrical parts on either side are called anchor claws. The anchor claws are the most critical component for the anchor to grip into the seabed. After a ship drops anchor, the anchor sinks to the seabed under the pull of the anchor chain. At the seabed, thanks to the action of the anchor rod, the plane where the anchor arm is located becomes perpendicular to the seabed, at which point the anchor claws come into contact with the seabed. Qingdao Tonghang Shipbuilding has been professionally engaged in the R&D and production of ship anchors—including Hall anchors, S-bend anchors, naval anchors, high-holdforce anchors, and steel floating buoys—for 18 years. Typically, the length of a ship’s anchor chain exceeds the water depth; therefore, the portion of the anchor chain lying on the seabed remains flat. When the ship experiences disturbances—such as being hit by a head sea—the anchor...

Maintenance of anchor chain and links

Steel for anchor chains needs to be high-performance, green steel plates that meet the new standards set by the shipbuilding industry. Taking high-strength steels used in large bulk carriers, container ships, oil tankers, and offshore engineering vessels as an example, currently, the proportion of high-strength plates (A32–A36) used in bulk carriers and container ships exceeds 60%, while the proportion used in oil tankers is around 30%. Now, do you know how to maintain anchor chains? Let’s discuss this topic together today. Maintenance of anchor chain links: 1. The tension of the anchor chain links should be appropriate—too tight increases power consumption and accelerates bearing wear; too loose can cause the chain to jump and even come off its track. 2. If the anchor chain becomes excessively long or has been used for a period of time...