Hot-Dip Galvanized Studless Anchor Chain | Open Link Grades U1, U2 and U3

Hot-Dip Galvanized Studless Anchor Chain | Open Link Grades U1, U2 and U3

Product Overview

The hot-dip galvanized studless anchor chain, also called an open link anchor chain, is supplied for marine anchoring arrangements that require a short-link chain without cross-studs. The open-link geometry removes the risk of loose studs and reduces component count, while the galvanized finish provides an additional corrosion-protection layer for storage, deck handling, and service in marine environments.

This page covers U1, U2, and U3 supply grades in nominal diameters from 12.5 mm to 70 mm. The chain is sourced from specialist chain factories and supplied as a traded product; the applicable standard, approved works status, heat-treatment condition, proof and break loads, galvanizing specification, and classification certificate scope must be confirmed for each order. Offshore mooring chain in R3 / R3S / R4 or equivalent grades is a separate technical and certification scope and should not be selected from the U-grade table on this page.

Quick Specifications

• Product type: Studless / open link anchor chain -> no cross-stud, avoiding stud-loosening issues and simplifying link inspection.
• Chain diameter: 12.5 mm to 70 mm -> covers the supplied marine anchor-chain range shown in the technical table.
• Grades: U1, U2, and U3 -> grade and heat-treatment condition must match the approved vessel or project specification.
• Shot length: 25.0 m to 27.5 m -> confirm the exact finished length, tolerance, joining arrangement, and number of shots before quotation.
• Link proportions: L = 6D and B = 3.6D in the supplied table -> useful for windlass, chain stopper, locker, and connection-interface checks.
• Construction: Flash-butt welded rolled steel bar -> weld-process control, flash removal, dimensional inspection, and traceability are key supply checks.
• Surface treatment: Hot-dip galvanized as the page focus -> zinc coating standard, coating mass / thickness, thread protection, and touch-up procedure are to be confirmed.
• Inspection scope: Material tests, proof load, break load, and specified NDT can be arranged -> final witnessing and certificate issue depend on the approved purchase and class inspection plan.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm the service: ship anchoring, replacement chain, special short-link arrangement, or a separately specified offshore mooring application.

Step 2: Confirm nominal diameter, grade, required proof load and break load, applicable standard, equipment-number basis, and approval drawing. Do not select solely by diameter.

Step 3: Confirm the complete chain arrangement: number and length of shots, end links / enlarged links if required, joining shackles, anchor shackle, swivel, and compatibility with the windlass and chain stopper.

Step 4: Confirm material and finish: U1 / U2 / U3, heat-treatment condition, hot-dip galvanizing standard and required coating thickness, or alternative black-painted / blasted finish.

Step 5: Confirm inspection and certificate scope before quotation: approved chain works, material traceability, proof and break testing, dimensional inspection, UT / MT requirements, class witnessing, and certificate issuer.

Step 6: Provide quantity, vessel type, installation position, destination, required delivery time, approved drawing or existing-chain photos, and any packing or preservation requirements.

Structure

Flash-butt welded open link | Studless short-link geometry | Weld and flash-removal zone | Interlocking link bearing surfaces | Galvanized external surface | Marking and traceability identification | End connection according to approved chain arrangement

Chain Supply, Testing & Quality Advantages

• Studless geometry eliminates the separate cross-stud, removing a known stud-loosening issue and allowing straightforward visual access around the link body.
• The absence of a stud can reduce weight compared with a comparable stud-link arrangement; the actual unit mass and system suitability must follow the supplied table and approved design.
• The open-link form can accommodate selected shackle arrangements without a dedicated end link in some systems, but the connection diameter, bearing area, articulation, and class approval must be checked before supply.
• Flash-butt welding, flash removal, link forming, dimensional control, and heat treatment where applicable should be performed under the approved chain works procedure.
• Proof-load and break-load testing are separate acceptance checks. Neither value should be presented as SWL, and the chain is not to be selected by applying an arbitrary safety factor to the table.
• Hot-dip galvanizing adds a sacrificial zinc layer, but coating thickness, adhesion, local repair, handling damage, and compatibility with chain pockets and moving interfaces remain project-specific.
• As a supply product, the quotation should identify the actual chain factory, approved manufacturing scope, certificate route, marking, test records, accessories, preservation, and packing rather than implying in-house manufacture.

Custom Attributes

• Product Category: Marine anchor chain supply -> this page covers galvanized studless / open link chain rather than stud-link chain.
• Nominal Diameter: 12.5-70 mm -> confirm against vessel design, handling equipment, and required test-load table.
• Grade: U1 / U2 / U3 -> grade designation must be tied to an identified standard and approved manufacturing route.
• Shot Length: 25.0-27.5 m -> exact finished length and tolerance to be stated in the purchase order.
• Construction: Flash-butt welded rolled steel bar -> weld process, flash removal, forming, and dimensional checks form part of supply quality control.
• Surface Treatment: Hot-dip galvanized -> coating standard and minimum zinc requirement are to be confirmed; black-painted or other finish can be quoted separately.
• Testing: Proof load / break load / material tests / specified NDT -> frequency, acceptance criteria, witnessing, and reporting follow the order and classification plan.
• Supply Status: Traded / distributed product -> sourced from specialist chain factories; manufacturer identity and works approval are confirmed for the order.
• Certificate Requirement: Available according to project scope -> classification certification is not automatic and must be agreed before production and testing.

How It Works

Anchor or termination receives line tension -> Interlocking studless links transfer axial load along the chain -> Link geometry permits articulation through the approved handling route -> Load is transmitted to the chain stopper, windlass, or approved mooring termination -> Chain is inspected, preserved, and stored after recovery

Applications

Ship anchoring systems | Workboats and service vessels | Replacement anchor-chain assemblies | Special short-link arrangements accepted by the selected class society | Offshore mooring projects only under a separate R-grade specification and approval basis

Certifications & Advantages

Classification inspection and certification can be arranged according to the applicable standard, approved chain works, material traceability, test scope, and project requirement. IACS publishes unified requirements but does not itself issue product certificates; the selected classification society or maker issues the applicable certificate.

Certification: CCS, NK, BV, ABS, DNV, LR, KR, IRS, RS, RINA, CRS, Makers Test Certificate.

Drawing & Photos

FAQ

Q1: What is the difference between a studless open link chain and a stud-link anchor chain?

A1: A studless link has no cross-stud, so there is no stud-loosening issue and the link body is easier to inspect. However, studless short-link chain is not a universal replacement for ship anchor chain. The vessel arrangement, applicable standard, windlass and stopper geometry, test loads, and classification acceptance must be confirmed.

Q2: How should the correct diameter and grade be selected?

A2: Use the vessel or project design basis, applicable chain standard, required proof and break loads, equipment-number or mooring analysis, and compatibility with the windlass, chain stopper, hawse pipe, anchor, and connecting accessories. The table values are test loads, not SWL.

Q3: Are galvanizing, NDT, proof testing, and class certificates included automatically?

A3: No. The quotation must define galvanizing standard and coating requirement, NDT method and frequency, proof and break test scope, witnessing, manufacturer approval, marking, and the certificate issuer. These items are supplied according to the confirmed order and project inspection plan.

Zhongyuan Ship Machinery Manufacture (Group) Co., Ltd. was founded in the 1990s and has developed into an integrated marine equipment manufacturer and project supply partner combining manufacturing, technical support, and export services. The group consists of four factories and one export trading company, with more than 300 employees, including over 20 experienced technicians and engineers. Our export company supports global customers with project communication, technical documentation, logistics coordination, and after-sales service.

Our factories are certified to ISO 9001, ISO 14001, ISO 45001, and related occupational health and safety management standards. We also hold type approval certificates from major classification societies such as DNV, LR, BV, and ABS, as well as works approval certificates, class-approved WPS procedures, and qualified welders. Our products can be supplied with certificates from IACS classification societies including DNV, ABS, LR, BV, CCS, RINA, KR, NK, IRS, and RMRS, depending on project requirements.

We manufacture a wide range of marine and offshore equipment, including deck equipment and machinery, mooring and towing equipment, deck outfitting, shafting components, rudder stocks, shaft and rudder systems.

In addition to our manufactured products, we also supply selected marine equipment through qualified partner manufacturers, including hydraulic cylinders, hydraulic power units, marine hardware, lifting and lashing equipment, hoisting and rigging products, lifeboats, rescue boats, launching appliances and davits, life-saving equipment, fire-fighting equipment, rubber fenders, rubber packing, marine pumps, valves, pipe fittings, multi-core pipes and accessories, steel wire ropes, mooring ropes, rope nets, anchors, anchor chains, and various marine chains.

Our main production facilities include CNC machining centers, CNC machine tools, CNC cutting machines, boring and milling machines, hydraulic presses, plate rolling machines, welding robots, welding equipment, shot blasting equipment, and dust-free painting workshops. These facilities enable us to support customized manufacturing and project-based production for shipbuilding, ship repair, offshore, and marine engineering projects.

We are committed to providing reliable, high-quality, and cost-effective marine equipment to customers worldwide. With our manufacturing capability, technical support, qualified supply network, and export coordination experience, Zhongyuan aims to be a trusted partner for shipyards, shipowners, offshore companies, and marine equipment distributors.