Marine Hatch Cover Pull Chain | 11-30 mm Welded Drag Chain

Product Overview

The marine hatch cover pull chain is a flash butt welded open-link chain used to transmit pulling force in compatible chain-driven cargo hatch cover systems. It runs through the original chain wheel, pocket wheel, guide or pulling arrangement to move the hatch cover during opening and closing. Typical use includes drag-type and chain-driven rolling hatch cover arrangements on bulk carriers and general cargo vessels.

Replacement selection must be based on the complete link geometry and system interface, not chain diameter alone. Chain diameter, pitch, inside width, outside width, material grade, proof load, breaking load, total length, link count and end connections should be checked against the hatch cover maker drawing or an approved original sample. This product is a hatch cover drive/pull chain; it is not an anchor chain, mooring chain or general-purpose lifting chain.

Quick Specifications

• Chain size range: 11 to 30 mm → covers the supplied replacement range for different hatch cover drive arrangements.
• Link pitch / inside length: 42 to 108 mm → must match the chain wheel or pocket geometry to prevent poor engagement.
• Inside width: 12.5 to 35 mm → affects clearance through guides, wheels and connecting components.
• Proof load: 57 to 399 kN → production or acceptance load reference; it is not the chain SWL.
• Breaking load: 116 to 798 kN → minimum reference value from the supplied table, subject to material grade and agreed test basis.
• Approximate mass: 2.39 to 18.22 kg/m → useful for total chain weight, handling, packing and freight calculation.
• Construction: flash butt welded, studless open-link chain → link weld quality and dimensional consistency are key manufacturing controls.
• Standard finish: black painted → self-colour, galvanized or project-specific coatings require confirmation before production.

Main Technical Parameters

Hatch Cover System Matching & Inquiry Guide

Step 1: Provide the hatch cover maker, vessel name or hull number, hatch cover type, original chain code and available system drawing or chain sample.

Step 2: Confirm chain diameter, pitch, inside width, outside width, overall length, link count, end links, connectors and any joining arrangement.

Step 3: Confirm required proof load, breaking load, material grade and test basis. Do not use proof load or breaking load as a working load limit.

Step 4: Confirm compatibility with the existing chain wheel, pocket wheel, guide, drive unit and chain storage path before ordering replacement chain.

Step 5: Confirm surface finish, corrosion environment, lubrication practice and whether black painted, self-colour or galvanized supply is required.

Step 6: State quantity or total length, packaging, inspection and certificate scope, destination, required delivery time and class requirement.

Chain Construction

Calibrated open links | Flash butt welded link joint | Controlled chain diameter and pitch | Defined inside and outside width | Continuous chain length | Optional end link or connecting arrangement | Black painted or project-specified finish

Manufacturing, Load Verification & Maintenance Advantages

• Flash butt welding provides a continuous welded link structure; weld alignment, trimming and the heat-affected area should be controlled under the approved manufacturing process.
• Chain diameter, pitch and link width are checked as a matched geometry because consistent engagement with the chain wheel is essential for smooth hatch cover travel.
• Material traceability and heat-treatment requirements can be controlled by batch when a specific steel grade or strength level is stated in the purchase specification.
• Proof loading and destructive breaking-load testing can be arranged according to the agreed inspection and test plan; test frequency and acceptance basis must be confirmed before production.
• Replacement chain should be checked together with chain wheels, pockets, guides and connectors for corrosion, abnormal wear, pitch mismatch or damaged engagement surfaces.
• Routine inspection should focus on link-crown wear, corrosion loss, bent links, cracked weld areas, local deformation and accumulated pitch elongation.

Custom Attributes

• Product Function: Hatch cover drive / pull chain → transmits pulling force in a compatible opening and closing mechanism.
• Chain Size: 11 / 14 / 15 / 16 / 18 / 19 / 20 / 22 / 30 mm → select by complete link geometry and system drawing.
• Link Geometry: Multiple A / B / C configurations → same chain diameter may have different pitch, width and mass.
• Material: Carbon steel → 20Mn2, 20MnV or other grades may be discussed but must be confirmed by order specification.
• Manufacturing Method: Flash butt welded links → dimensional calibration and weld quality are key inspection points.
• Surface Treatment: Black painted as supplied basis → self-colour, normal galvanizing or hot-dip galvanizing is project-specific.
• Load Data: Proof load and breaking load → qualification values, not SWL or WLL.
• Supply Form: Cut length, complete loop or system-specific chain assembly → end fittings and joining method must be defined.
• Packaging: Wooden case, carton, drum or pallet → selected by chain length, unit mass, finish and transport method.

How It Works

Drive unit applies pulling force → Chain engages the chain wheel / pocket arrangement → Link-by-link movement transfers force along the chain path → Hatch cover rolls or travels through its designed opening or closing sequence → Chain returns to the storage or guide arrangement

Applications

Chain-driven cargo hatch cover systems | Drag-type hatch cover arrangements | Side-rolling hatch cover pull systems | Rolling hatch cover replacement projects | Bulk carriers | General cargo vessels | Ship repair and retrofit

Inspection, Testing & Documentation

Dimensional inspection, proof-load testing, breaking-load testing, material certificates and maker test documentation can be arranged according to the purchase specification. Classification inspection is available upon request and remains subject to the applicable society rules, approved test scope and survey attendance.

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

Drawing & Photos

FAQ

Q1: What information is required to replace an existing hatch cover chain?

A1: Provide the original maker or chain code, chain diameter, pitch, inside and outside width, total length or link count, end connection, required loads and a drawing or representative sample. The chain wheel and guide condition should also be checked.

Q2: Can the proof load or breaking load be used as the chain SWL?

A2: No. Proof load and breaking load are test or strength references. They are not a working load limit. The hatch cover system designer or original equipment maker should define the operating load and required design margin.

Q3: Can a new chain section be mixed with an existing worn chain?

A3: Only after engineering confirmation. Used chain may have corrosion, wear and pitch elongation that cause uneven chain-wheel engagement. Full-chain replacement or a verified matched section is normally safer than an unassessed mixed installation.