Casting Steel 6" 8" 10" Marine Button Chock ASTM A27-70-36 Ship Mooring

Product Specification

Cast Steel Button Chocks 6", 8" & 10" | ASTM A27-70-36 for Inland Barges

Product Overview

The 6", 8", and 10" cast steel button chocks are deck-welded line-retaining fittings developed for inland barges, towboats, workboats, and other North American-style river vessel arrangements. Unlike a conventional open or closed chock that guides a line through an opening, a button chock is primarily used to receive and retain the eye of a mooring line or wire during tow make-up, shifting, and barge mooring operations.

The three models use ASTM A27/A27M Grade 70-36 cast steel and have nominal size designations of 6", 8", and 10". Selection should be based on the line or wire eye geometry, intended load basis, deck layout, welding interface, and local deck reinforcement. The supplied dimensions and weights support initial selection and quotation, but the final production drawing and vessel structural review should govern installation.

Quick Specifications

• Product type: Cast steel button chock → deck fitting for retaining the eye of a line or wire during inland barge tow make-up and mooring.
• Primary market and vessel type: North and South American inland waterways → commonly specified for barges, workboats, towboats, and river-service vessels.
• Nominal size range: 6", 8", and 10" → three common deck-hardware sizes with approximate weights from 38 to 144 lb.
• Material: ASTM A27/A27M Grade 70-36 cast steel → heat-treated and mechanically tested carbon steel casting grade.
• Installation: Welded to the deck structure → weld procedure, weld-zone preparation, deck reinforcement, and load direction require vessel-specific confirmation.
• Line interface: Button head and recessed throat → retains a line or wire eye without describing the product as a bollard or lifting point.
• Surface condition: As-cast/unpainted weld-ready supply or specified blasted and primed finish → coating sequence should be coordinated with shipyard welding.
• Inspection options: Material certification, MT, RT, and agreed pull-load testing → available according to project scope and acceptance criteria.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm the required button chock model: 6", 8", or 10", and provide the vessel or barge deck arrangement drawing.

Step 2: Confirm the line or wire type, eye size, intended tow make-up or mooring use, lead direction, and project design load basis.

Step 3: Confirm the deck installation position, available clearance around the button head, deck plate thickness, reinforcement, and shipyard weld detail.

Step 4: Confirm ASTM A27/A27M Grade 70-36 material, heat-treatment record, material certificate, and any class or owner inspection requirement.

Step 5: Confirm finish: as-cast/unpainted weld-ready condition, Sa 2.5 blasting plus epoxy shop primer, galvanized finish, polished stainless steel option, or project coating system.

Step 6: Provide quantity, required certificate and test scope, delivery destination, required delivery time, and drawing or reference photo if available.

Structure

Cast steel button body | Overhanging head | Line-retaining throat | Rounded line-contact surface | Deck-welded base | Controlled weld interface | As-cast or specified surface treatment

Casting, Welding & Mooring Advantages

• The button geometry is suited to the eye of a line or wire, helping keep the eye seated during tow make-up and barge mooring operations.
• Rounded cast surfaces can be dressed and smoothed to reduce sharp local contact with synthetic line, fiber rope, or wire-rope eyes.
• The 6", 8", and 10" range matches common American inland barge deck-hardware practice and provides a practical size progression for replacement or newbuild projects.
• ASTM A27/A27M Grade 70-36 is a heat-treated and mechanically tested carbon steel casting grade; the purchaser and shipyard should still establish a suitable welding procedure for the actual casting and deck materials.
• An as-cast or unpainted weld-zone condition can simplify deck welding. If shop primer or galvanizing is specified, weld-zone preparation and coating repair should be agreed before production.
• MT, RT, and pull-load testing can be arranged when required, but the method, test load, acceptance criteria, witness requirement, and certificate wording must be agreed in the order.
• The welded base transfers service forces into the vessel structure; local deck reinforcement and weld sizing remain part of the vessel or shipyard structural design.

Custom Attributes

• Product Type: Cast steel button chock → line-eye retaining deck fitting for barge tow make-up and mooring.
• Nominal Sizes: 6" / 8" / 10" → select according to the line or wire eye, deck space, and approved drawing.
• Material: ASTM A27/A27M Grade 70-36 → carbon steel casting grade with heat treatment and mechanical testing.
• Typical Vessel Application: Inland barge / towboat / workboat → particularly relevant to American river and barge deck-hardware arrangements.
• Installation: Deck welded → weld procedure, deck reinforcement, and surrounding clearance to be confirmed by the vessel design.
• Surface Treatment: As-cast, Sa 2.5 blasted and epoxy shop primed, galvanized, polished, or customized → final finish depends on welding and coating sequence.
• Inspection: Material certificate, MT, RT, and pull-load test as specified → not assumed as standard deliverables unless included in the order.
• Load Rating: To be confirmed → no SWL, MBL, test load, or permissible load is inferred from size, material grade, or product weight.

How It Works

Line or wire eye is placed over the button head → The eye seats in the recessed throat → Rounded contact surfaces retain and guide the eye during tow make-up or mooring → Service forces pass through the welded base into the reinforced deck structure

Applications

Inland barges | Tank barges | Dry cargo barges | Towboats and workboats | Push-tow and tow make-up arrangements | River terminals | Barge repair and replacement projects | Marine deck mooring stations

Certifications & Advantages

ABS approval documentation, material certificates, maker certificates, NDT reports, and witnessed testing can be arranged according to project requirement, order scope, and applicable class approval procedure. Certificate availability should be confirmed before quotation.

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

Drawing & Photos

FAQ

Q1: How should the 6", 8", or 10" button chock be selected?

A1: Select the model according to the line or wire eye dimensions, service arrangement, deck space, lead direction, project design load, and approved vessel drawing. The nominal size alone is not a complete load-selection basis.

Q2: Is the nominal size or product weight the SWL?

A2: No. The 6", 8", and 10" designations describe the model and throat geometry, while the listed weight is for handling and freight reference. SWL, MBL, permissible load, and test load must not be inferred without an approved load basis and structural calculation.

Q3: Should the button chock be painted before deck welding?

A3: American barge hardware is often supplied as-cast or unpainted at the weld interface to support shipyard welding. Blasting, shop primer, galvanizing, or other coatings can be supplied, but weld-zone masking, removal, and coating repair should be agreed with the shipyard.