What Is an End Shackle in Anchor Chain System

An end shackle (also known as an anchor end shackle) is a critical anchor chain fitting in any marine mooring system. Its primary function is to establish a reliable load-bearing connection between the anchor’s crown shackle and the first link or swivel of the anchor chain system.

This connection point directly affects the safety and reliability of the entire mooring system. High-performance mooring chain end shackles ensure stable load transfer even under extreme marine conditions.

As a leading supplier of anchor chain end shackles, OLIPORTS understands that every link is critical. Our manufacturing facilities incorporate advanced testing protocols to ensure that every anchor shackle we deliver meets the highest industry standards.

Anchor End Shackle Specifications & Material

Key Features of Anchor End Shackle for Marine Mooring

OLIPORTS anchor chain end shackles are manufactured using advanced forging and heat treatment processes to ensure consistent and reliable performance. They are specifically designed for harsh marine environments:

Superior Material Composition: Manufactured from high-strength forged steel and alloy steel. With higher tensile strength, they can withstand the immense pressure of deep-sea anchoring.

Unique Oval Pin Design: OLIPORTS end shackles feature a precision-engineered oval pin. This prevents rotation and ensures a more secure assembly of the anchor chain shackle

Standardized Grading: OLIPORTS offers two grades: Grade U2 and Grade U3. This allows shipowners to match the shackle strength to the specifications of their stud link anchor chains

End shackles are structurally similar to D-type shackles or bow shackles, but they are specially designed in accordance with anchor chain standards and are not interchangeable with standard lifting shackles.

Overall Dimensions of End Shackle

At OLIPORTS, all anchor chain end shackles undergo strict dimensional control to ensure a precise fit with the system.

How to Read End Shackle Dimensions | Anchor Chain Size (d) Explained

In this drawing, “d” represents the anchor chain diameter, and all dimensions are expressed as multiples of this value (e.g., 1.4d, 5.2d).

This design ensures that anchor chain end shackles of different sizes are consistent in terms of strength and structure.

Key Dimensions in this end shackle drawing:

• Pin diameter (1.4d): Determines shear strength
• Body width (5.2d): Affects connection fit
• Overall length (8.7d): Determines installation space

All sizes of OLIPORTS end jointing shackles comply with the standard proportions for anchor chain fittings, ensuring compatibility with the following systems:

• U2 / U3 anchor chains
• ISO / IACS standards
• Marine mooring systems

End Shackle Size Chart

OLIPORTS end joining shackles are manufactured in accordance with ISO 1704. Below is the Kenter shackle size chart for our reference.

How to Connect Anchor Chain to Anchor

For large vessels, we recommend using heavy-duty mooring-grade end-connection shackles to prevent fatigue failure. OLIPORTS provides free installation guides and torque specification tables.

How to Choose Anchor Chain End Shackle | Size, Grade & Load Guide

Determining the anchor chain diameter: You must select a shackle that matches the chain diameter to ensure a reliable connection. All end shackle sizes are designed based on this parameter.

Choose the Correct Grade (U2 vs. U3 Shackle): The higher the grade, the greater the breaking load. OLIPORTS recommends U2 shackles → for general marine applications; U3 shackles → for heavy-duty / offshore environments

Load Capacity: Ensure the Working Load Limit (WLL) matches your stud link anchor chain.

Material: Choose alloy steel for deepwater operations and carbon steel for standard nearshore mooring.

Certification: Always look for Grade U2 / Grade U3 certification issued by organizations such as ABS, LR, or DNV.

FAQ of End Shackle