MOORING EQUIPMENT

Offshore mooring chains

The offshore mooring chain is a crucial component employed for fixing vessels and marine platforms (such as offshore oil drilling platforms, offshore wind power platforms, etc.) at specific locations in marine areas. Its primary function is to endure the environmental external forces acting upon the vessel or platform (such as wind, waves, currents, ice, etc.) and transfer these forces to the anchoring foundation at the seabed, thereby guaranteeing the stability and safety of the vessel or platform at sea. For a large container ship that is moored at a port for a prolonged period for loading and unloading cargo, the mooring chain firmly connects the ship’s hull to the mooring piles at the pier, preventing the vessel from drifting under the influence of wind, waves and currents.

Common Strength Level (R3)
Applicable to small vessels or those operating in calm sea areas. Tensile strength typically ranges between 400 and 600 MPa.It employs common carbon steel along with a small quantity of elements such as manganese and silicon to enhance the strength and toughness of the steel.The chain links are fabricated using the hot forging process. The forged chain links undergo normalizing treatment, which can refine the grain size and enhance the comprehensive performance.

Medium strength level (such as R3S)
The strength is between the ordinary strength and high strength, and it is a medium strength mooring chain, suitable for bulk carriers, general cargo vessels. The minimum breaking load corresponds to the tensile strength of about 600-800 MPa.Mainly high-quality carbon steel or low-alloy steel. The chain links are made by hot forging, but the temperature control and forging ratio during the process require stricter parameters.

High Strength Grade (R4)
Possessing high strength, it is the preferred option for large vessels and those operating in adverse marine environments, such as large oil tankers, liquefied natural gas (LNG) ships, and ocean-going container ships. The tensile strength corresponding to its minimum breaking load is typically above 800 – 1000 MPa, capable of ensuring the mooring safety of vessels in extreme conditions like violent winds, huge waves, and strong currents.Utilizing high-strength alloy steel with a relatively high content of alloy elements. The chain links adopt precise hot forging techniques.

Higher Strength Levels (R5, R6)
The tensile strength corresponding to the minimum breaking load of grade R5 typically exceeds 1,000 MPa, and grade R6 has an even higher strength, capable of withstanding more extreme tensile conditions. It is suitable for special marine environments (such as deep sea and polar regions).Grade R5 employs higher-strength special alloy steel with a more complex alloy composition. The material of grade R6 is even more advanced.The control precision of parameters during hot forging is higher.