What Are Anchor Chains Used For?
Main Application Fields And Case Analysis of Anchor Chain
As the core material of marine engineering, anchor chain plays a key role in ship mooring, marine facility fixation, emergency operation and other fields with its high strength, corrosion resistance and reliability. The following is an explanation based on real cases:
1. Ship Mooring And Fixation
The anchor chain connects the hull and the anchor, transmits grip and buffers external force impact, ensuring the safe mooring of the ship in the port, anchorage or shelter.
Bulk carrier Qingdao Port mooring:When a bulk carrier with a load of 200,000 tons enters Qingdao Port, it needs to drop a large-sized marine anchor chain with a gear. The tension of this large-sized anchor chain needs to withstand strong winds and waves and tidal impacts to ensure the safety of loading and unloading operations.
VLCC Singapore offshore shelter:During the typhoon season, very large crude tankers (VLCCs) often go to Singapore offshore anchorages for shelter, and they also need to use large-sized marine anchor chains with gears, generally 27.5M per section. The specific length depends on the coast, but it needs to be able to withstand a 16-level typhoon and a wave height of 5 meters to ensure the stability of the mooring system.
2. Fixing of Marine Engineering Facilities
Anchor chains are used to fix floating structures such as offshore wind power platforms and FPSOs to ensure their stability in complex sea conditions.
"Three Gorges Leader" floating wind power platform:China's first deep-sea floating wind power project, the platform is connected to the seabed anchor piles through 12 large-sized non-sprocket mooring chains. Because it needs to be immersed in water for a long time, a mooring chain with strong corrosion resistance is selected. This design can withstand extreme sea conditions in the South China Sea and ensure an annual power generation of more than 22 million KWH.
Brazil's "Mero-4" deep-sea oil and gas field FPSO:The FPSO of this offshore oil field project is fixed with a gear mooring chain. The length of the mooring chain is determined according to the actual design of the project and connected to the seabed with a large grip marine anchor. It can withstand high pressure and strong currents in the deep sea to ensure the safety of operations with a daily output of 180,000 barrels of crude oil.
3. Stability of Offshore Operating Platforms
Anchor chains provide stability against wind and waves and tidal currents for marine ranches, scientific research platforms, etc. to ensure operational safety.
Blue granary, marine ranch：Anchor chains are used to fix deep-sea aquaculture cages and aquaculture vessels to prevent equipment drift or damage.
Ocean Farm 1, a Norwegian SalMar aquaculture vessel:The vessel is fixed by 8 non-stall anchor chains. The length of the anchor chains is designed according to the seabed depth. The patented anchor of the China National Offshore Oil Corporation is connected through a shackle and a mooring plate to withstand strong winds and waves in the North Sea. Its annual output reaches 15,000 tons of salmon, and the stability of the anchor chain ensures the efficiency of aquaculture.
Fjord farm of Cermaq, Chile:The salmon aquaculture cages in the southern fjords of Chile are fixed by φ32mm staggered anchor chains. The length of the anchor chain is determined according to the design of the sea area and connected to the marine anchor on the seabed. This specification adapts to the complex water flow of the fjord, ensures the stable growth of salmon in low-temperature waters, and ensures that the fishery is not damaged by wind and waves.
Scientific research platform：Anchor chains are used to fix deep-sea observation stations to ensure the accuracy of long-term monitoring data.
China's "South China Sea Ocean Observation Network":The observation network consists of multiple deep-sea observation stations, each of which is fixed by a mooring chain with a length of more than 1,000 meters, linking each station. It can monitor seawater temperature, salinity and other parameters for a long time, providing key data for marine scientific research.
4. Emergency And Maneuvering Assistance
Anchor chains can be used to fix the hull or assist in refloating in emergency situations such as ship grounding and out-of-control wind and waves; when sailing in narrow waterways, anchoring can control the ship's speed or posture.
"Ever Given" Suez Canal grounding rescue:In 2021, the "Ever Given" ran aground in the Suez Canal. During the rescue, the tugboat connected the bow with an anchor chain and used the anchor chain tension to assist in refloating. Although it ultimately relied on dredging and towing to get out of trouble, the anchor chain played a key role in the rescue.
Ship shelter during Typhoon Mangkhut:In 2018, Typhoon Mangkhut hit the coast of China. A bulk carrier with a load of 100,000 tons is fixed by a studded anchor chain, successfully withstanding a 14-level typhoon and a 4-meter wave height, avoiding drift or collision.
5. Special-purpose Mooring
Anchor chains are used for permanent facilities such as buoys, buoys, and lightships, or as ice anchors for icebreakers to ensure their stability in harsh environments.
Floats and buoys：Anchor chains fix channel buoys and ocean monitoring buoys to ensure the safety of waterways and sea areas.
China East China Sea Channel Buoys:The buoys are fixed by φ32mm studless anchor chains with a length of about 100 meters, which can withstand typhoons and strong currents to ensure smooth waterways.
Lightships
Anchor chains fix lightships to provide navigation for ships at night or in bad weather.
San Francisco Bay Lightships:The lightships are fixed by φ56mm studded anchor chains with a length of about 300 meters, which can withstand strong winds and waves in the bay area and provide reliable navigation for passing ships.
Ice anchor for icebreakers：As part of the ice anchor, the anchor chain fixes the icebreaker to prevent drifting in ice operations.
Russian "50th Anniversary Victory" nuclear-powered icebreaker:When the ship sails in the Arctic, the ice anchor is fixed by a φ110mm studded anchor chain. The length of the anchor chain is about 200 meters, which can withstand the squeeze of thick ice layers and ensure the safety of icebreaking operations.
6. The Difference Between Studded And Studless Anchor Chains:
Studded anchor chain: There are cross bars between the chain links, which are stronger and suitable for large ships and marine engineering facilities.
Studless anchor chain: There are no cross bars between the chain links, which are lighter and suitable for small and medium-sized ships and weight-sensitive facilities.
Conclusion：
As the "invisible guardian" of marine engineering, the anchor chain plays a key role in the fields of ship berthing, marine facility fixation, emergency operation, etc. By reasonably selecting the type and specification of anchor chains, the safety and stability of marine facilities in complex environments can be ensured. With the deepening of marine development, anchor chain technology will continue to innovate and provide stronger support for the marine economy.