Casting Mooring Chock Liner 2× Life

The Road to Innovation for Marine Mooring Chocks

The story begins with our foundry receiving a project from a large shipyard to develop marine mooring chock liner.

Marine mooring chocks are vital for guiding cables, distributing stress, and protecting hulls. But they're prone to damage due to frequent use and environmental corrosion, which impacts ship efficiency and safety. This article analyzes damage causes, maintenance issues, solutions, and prospects. 

Current Status of Mooring Chocks: Why Do They Keep Breaking Down?

Damage is caused by design flaws (e.g., insufficient hole wall thickness), manufacturing defects (e.g., slag inclusions), improper installation, and overuse. The manufacturing process is mainly casting, and material choice affects durability. The number of mooring chocks varies by vessel type and size. Damage results from a combination of factors, not just design flaws. 

The Maintenance Dilemma—"Removal" is More Expensive than "Replacement"

Severely damaged mooring chocks are costly to repair. The vessel must go to a repair shop, where professionals replace the chock. This requires specialized tools, manpower, and resources, leading to high costs and operational downtime, exacerbating economic losses.

Conventional Approach: Modifying the Design Scheme

Modifying the Design and Recertification

Optimizing design improves durability and safety, but recertification by the classification society is time-consuming. Complete replacement is costly and disrupts operations. 

Strengthening Manufacturing Process Control

Controlling casting parameters and optimizing heat treatment improves quality but can't solve design and usage-related damage problems. 

Innovative Approach: Giving the "Hole" a Replaceable "Liner"

Equipping mooring chocks with protective liners (stainless steel or cast nylon) is a feasible solution. 

Stainless Steel Protective Liner

Parameters: High strength and corrosion resistance, with a bending strength of 200 - 300 MPa, a notched impact strength of approximately >50 kJ/m², and an operating temperature range of -40℃ to +800℃. Heavier and requires welding for installation.

Advantages:

Exceptional Strength: Its high bending strength (200 - 300 MPa) and notched impact strength (>50 kJ/m²) enable it to withstand high-stress situations during mooring operations. Whether it's the force from cables or external impacts, the stainless steel liner can hold up, reducing the risk of damage to the mooring chock.

Superior Corrosion Resistance: Operating in a marine environment, mooring chocks are constantly exposed to saltwater, which is highly corrosive. The stainless steel liner can resist corrosion effectively, maintaining its structural integrity over a long period. This ensures that the liner can continue to protect the mooring chock even in harsh conditions.

Long Service Life: Theoretically, its service life can be extended by 15 - 20 years. This longevity means less frequent replacement, reducing maintenance costs and downtime for the vessel. Ships can operate more smoothly without the need for regular liner replacements, improving overall operational efficiency.

High-Temperature Tolerance: With an operating temperature range of -40℃ to +800℃, it can function well in extreme temperature conditions. Whether in cold polar regions or near engine rooms with high temperatures, the stainless steel liner remains stable, providing reliable protection.

In mechanical testing experiments, stainless steel shows an undeniable advantage in material properties. After rigorous shipyard testing, including mechanical, fatigue, and simulated scenario tests, the optimal solution for protecting mooring chocks will be widely applied.

We would like to say: There are many foundries in China, but a foundry with a soul is truly one in a million.

More Links:

What is Green Casting, And How Can It Be Achieved?

What is the Casting Process ?

The Application of Metal Castings