Stud-Link Marine Anchor Chain | U1 U2 U3 Flash-Butt Welded for Ship Anchoring

Product Overview

The stud-link marine anchor chain is a flash-butt welded chain cable supplied for ship anchoring systems. Each common link contains a centrally fitted stud that supports the link geometry, helps limit excessive deformation and twisting, and provides stable engagement with the windlass cable lifter. The chain is selected as part of the complete anchoring arrangement, including the anchor, windlass, chain stopper, hawse pipe, chain locker and connecting accessories.

The supplied range is 12.5–70 mm in U1, U2 and U3 grades, with shot lengths normally ordered between 25.0 m and 27.5 m. ISO 1704:2022 provides the recognized dimensional basis for stud-link anchor chains, while applicable classification rules and IACS UR W18 provide requirements for approved manufacture, materials, heat treatment, proof testing, breaking-load testing, marking and certification. This page concerns ship anchor chain; offshore permanent mooring chain grades such as R3, R3S, R4 and higher are separate products and require a different specification.

Quick Specifications

• Product type: Stud-link marine anchor chain → used between the ship’s anchor and windlass / chain locker anchoring arrangement.
• Construction: Flash-butt welded rolled-steel links with fitted studs → supports link shape and stable cable-lifter engagement.
• Grade options: U1 / U2 / U3 → final grade follows vessel equipment calculation, class rule and approved chain-works scope.
• Nominal diameter: 12.5–70 mm → detailed approved dimensions and mass must be confirmed against the manufacturer’s class drawing.
• Shot length: 25.0–27.5 m according to order → 27.5 m is the standard chain length referenced for class proof-load testing in IACS UR W18.
• Testing basis: dimensional inspection, proof-load test, breaking-load test and grade-dependent mechanical tests → survey scope is confirmed before production.
• Surface condition: black painted, grit-blasted or hot-dip galvanized when accepted by the project and class → coating is applied after required inspection and testing.
• Supply status: sourced from class-approved chain manufacturers → class certificate, maker documents and material traceability are arranged according to the purchase scope.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm that the requirement is for a ship stud-link anchor chain, then provide vessel type, class society, equipment number or anchoring arrangement data.

Step 2: Confirm nominal diameter and grade U1, U2 or U3 from the class-approved equipment calculation, anchor specification and windlass cable-lifter dimensions.

Step 3: Confirm total chain length, length per shot, odd-number link arrangement where required, and the required end links, enlarged links, Kenter joining shackles, swivel or anchor shackle.

Step 4: Confirm heat-treatment condition, surface finish, marking and whether replacement chain must match an existing chain, wildcat pocket and onboard accessory set.

Step 5: Confirm inspection and certificate scope: nominated class society, survey attendance, material traceability, proof / break tests, mechanical tests and any additional NDT requirement.

Step 6: Provide quantity, delivery destination, required delivery time, packing requirement and the existing chain certificate, drawing or clear dimensional photographs when available.

Structure

Flash-butt welded common links | Centrally fitted steel studs | Link crown and weld zone | Chain shot | End link and enlarged link | Kenter joining shackle | Swivel / anchor shackle according to anchoring arrangement

Manufacturing, Testing & Traceability Advantages

• The chain is supplied from works approved by the nominated classification society for the ordered grade, diameter, manufacturing route and heat-treatment condition.
• Rolled bar identification and heat-number control maintain traceability from incoming chain steel through link forming, flash-butt welding, heat treatment, testing and final certification.
• Link diameter, five-link length, stud position, stud fit and dimensional tolerances are controlled against ISO 1704 or the class-approved design.
• Flash-butt weld parameters and flash removal are production-critical points; the weld area is visually examined before coating, with additional inspection arranged only when specified.
• Stud welding, where used, follows an approved procedure and is completed before final heat treatment. Stud position and fit are checked to avoid unacceptable offset or loose seating.
• Each 27.5 m chain length is proof-load tested under the applicable class procedure; breaking-load samples and grade-dependent mechanical tests are taken according to the approved survey plan.
• Finished chain lengths are marked with grade, certificate number and society stamp when class certified, allowing the delivered shots to be linked to the test and material documentation.

Custom Attributes

• Standard: ISO 1704:2022 / applicable class rule → confirm the dimensional standard and class edition stated in the purchase specification.
• Grade: U1 / U2 / U3 → grade determines material properties, heat treatment and certified proof / breaking loads.
• Diameter: 12.5–70 mm → final size is selected by vessel anchoring equipment requirements, not by chain weight alone.
• Shot Length: 25.0–27.5 m → special length and end-link configuration are subject to chain-works and class confirmation.
• Surface Finish: Black paint / grit-blasted / hot-dip galvanized → coating must be compatible with the required inspection sequence and project specification.
• Accessories: Joining shackle / end link / enlarged link / swivel / anchor shackle → supply as a matched grade and diameter system when required.
• Certification: According to nominated class and approved works scope → certificate availability is confirmed before order, not assumed for every stock chain.

How It Works

Anchor is deployed → Stud-link chain runs through the hawse pipe and windlass cable lifter → Studs support link geometry and stable pocket engagement → Chain tension is controlled by the windlass brake and chain stopper → Anchor is recovered and chain is washed and stowed in the chain locker

Applications

Cargo ships | Bulk carriers | Tankers | Container ships | General cargo vessels | Workboats | Newbuilding anchoring systems | Replacement anchor-chain shots | Spare chain lengths and certified accessories

Certifications & Advantages

Classification certification can be arranged through the approved chain manufacturer according to the ordered grade, diameter, heat treatment, test scope and survey plan. IACS establishes unified technical requirements; the individual classification society performs or accepts the survey and issues the applicable product certificate.

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

Drawing & Photos

FAQ

Q1: How should U1, U2 or U3 anchor-chain grade be selected?

A1: Use the vessel’s class-approved anchoring equipment calculation, chain diameter, anchor specification and windlass cable-lifter design. A higher grade should not be substituted automatically because the complete chain, accessories, windlass and class approval must remain compatible.

Q2: Are UT and MT performed on every anchor-chain shot?

A2: Not as a universal default. Standard class scope includes dimensional inspection, proof-load testing, breaking-load testing, visual examination of the flash-butt weld and grade-dependent mechanical tests. UT, MT or other NDT should be stated in the inquiry and agreed with the manufacturer and class society.

Q3: Can this U1 / U2 / U3 chain be used as an offshore permanent mooring chain?

A3: Not without a separate approved specification. Offshore mooring grades such as R3, R3S, R4, R4S and higher have different material, toughness, fatigue, manufacturing and certification requirements and should be quoted as a separate product.