There are many reasons for using iron chains instead of wire ropes as anchors on ships, mainly including the following points:

　　Strength and Durability: Iron chains (especially anchor chains) are usually made of steel with high tensile strength, with high wear and impact resistance. This material property makes the iron chain less likely to break when subjected to huge tension, and is suitable for fixing large ships.

　　Corrosion resistance: The anchor chain needs to have good corrosion resistance when used in seawater. Iron chains can provide additional protection by special surface treatments such as hot-dip galvanizing or coated with anti-corrosion materials to reduce seawater corrosion.

　　Cost-effectiveness: Compared to wire ropes, iron chains are cheaper and are easy to produce and maintain on a large scale. In addition, the replacement and repair of iron chains is relatively simple, which helps reduce the overall maintenance cost.

　　History and tradition: Iron chains have been used as ship anchor chains for hundreds of years and are designed and used very maturely. In long-term navigation practice, iron chains have proven their reliability and effectiveness.

　　Compatibility: The design of the anchor chain matches the anchor winch system of the ship. Anchor winches are usually designed with specific sprockets and chain makers, which are suitable for the size and shape of the chain, ensuring that the anchor chain can be wound and released smoothly.

　　Specifications and Standards: IMO and classification societies have strict specifications and standards for ship anchor chains, which are usually formulated based on the performance and characteristics of the chain. The use of iron chains that comply with these specifications ensures the safety and compliance of the ship.

　　Accessories of anchor chains: Accessories of anchor chains, such as swivel rings, shackles, etc., are usually made of steel, and the connection and matching with iron chains are more reliable and convenient.