Cast Steel Single Bitt Bollard for Barges and Workboats | ASTM A27-70-36 Thru-Deck & Flush Weld Types

Cast Steel Single Bitt Bollard for Barges and Workboats | ASTM A27-70-36 Thru-Deck & Flush Weld Types

Product Overview

The ASTM A27-70-36 cast steel single bitt bollard is a welded deck mooring fitting for inland river barges, towboats, pushboats, small service vessels, and workboats. It is used with rope or wire lines for barge coupling, checking, and mooring operations where a single vertical bitt and a compact deck footprint are preferred.

The supplied range covers 8 in and 10 in single bitt configurations, including square-base heavy-duty thru-deck, round-base thru-deck, round-base flush type, and an additional 8 in square-base item requiring final type confirmation. Material traceability, heat treatment, casting soundness, weld-zone preparation, FEA review, pull test, and ABS / class inspection scope should be confirmed according to the vessel project requirement.

Quick Specifications

• Product type: Cast steel single bitt bollard → compact deck mooring point for barges, towboats, workboats, and small river vessels.
• Nominal bitt diameter: 8 in and 10 in → matches common inch-based deck hardware selection used in the North American inland vessel market.
• Installation forms: thru-deck heavy-duty, round-base thru-deck, round-base flush type, and square-base option → select according to deck penetration, weld interface, and replacement drawing.
• Material grade: ASTM A27-70-36 C-Mn cast steel or equivalent → heat-treated cast steel with material certificate and mechanical test report according to order scope.
• Rope-contact surface: smooth and free from harmful burrs → helps reduce rope cutting risk during coupling, checking, and mooring line handling.
• Casting quality control: material mechanical test, heat treatment record, MT / PT / RT when required → gas porosity, slag inclusion, and sub-surface indications are controlled within specified acceptance criteria.
• Engineering support: FEA strength calculation and pull test can be arranged when specified → useful for reviewing stress concentration at the bitt root, base transition, and welded deck interface.
• Certificate scope: ABS approval / class inspection and mill material certificate can be arranged according to project requirement → not treated as default for every order.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm the required single bitt size: 8 in or 10 in, and provide the vessel drawing or replacement part reference if available.

Step 2: Confirm installation form: square base, round base, thru-deck, heavy-duty thru-deck, flush type, or other deck arrangement.

Step 3: Confirm application vessel type: inland river barge, towboat, pushboat, workboat, small service vessel, or other marine deck application.

Step 4: Confirm load basis before production: intended line / wire size, rope MBL if known, design safety factor, required SWL if specified, pull-test requirement, and deck reinforcement drawing.

Step 5: Confirm material and inspection requirement: ASTM A27-70-36 or equivalent, heat treatment, material mechanical test, MT / PT / RT area, and acceptance criteria.

Step 6: Confirm surface treatment, coating after welding, quantity, delivery destination, required delivery time, ABS / class inspection scope, and required certificate package.

Structure

Cast steel single bitt body | Smooth rope-contact post | Square or round base | Thru-deck or flush welded installation | Weld-preparation area | Heat-treated casting | Optional inspection and pull-test arrangement

Casting, Welding & Engineering Advantages

• ASTM A27-70-36 or equivalent cast steel is suitable for cast marine deck hardware where a compact bitt shape, weldable base, and controlled mechanical property are required.
• The bitt post, base transition, and radius-changing areas are designed to be smooth to reduce local stress concentration and avoid sharp edges that may damage mooring rope.
• Heat treatment and material mechanical testing support strength consistency; the actual certificate package should follow the purchase order and inspection scope.
• Gas porosity, slag inclusions, and sub-surface casting indications are controlled within agreed acceptance criteria. The page intentionally avoids zero-defect claims because marine castings are inspected by acceptance level.
• MT or PT can be applied to accessible surfaces, and RT / X-ray inspection can be arranged for critical areas where force is concentrated, such as the bitt root and base transition, when required.
• Weldability depends on casting condition, weld-zone preparation, deck material, shipyard WPS, and class requirement. The deck welding procedure, preheat, and post-weld inspection should be confirmed by the shipyard or project engineer.
• FEA strength calculation can be used to review stress distribution around the single bitt post, base transition, deck penetration, and weld interface when the project requires engineering verification.
• Pull test can be arranged according to project requirement; the pull direction, test load, holding time, acceptance criteria, and witness requirement must be defined before production.

Custom Attributes

• Product Type: Single Bitt Bollard → one vertical bitt for compact deck mooring, checking, and barge line handling.
• Target Application: Inland river barges / towboats / pushboats / workboats → suitable for the North American and American inland vessel market when confirmed by vessel drawing.
• Material: ASTM A27-70-36 C-Mn cast steel or equivalent → final material equivalency and certificate wording should be confirmed before order.
• Installation: Thru-deck or flush welded arrangement → deck penetration, weld length, backing structure, and reinforcement must match the vessel design.
• Surface Treatment: Sandblasting as supplied data → final coating normally follows shipyard paint specification after installation.
• Casting Quality Control: Porosity / slag inclusion control within specified criteria → MT, PT, or RT can be selected according to inspection plan.
• FEA Review: Available according to project requirement → used for stress concentration and base transition review, not a substitute for class approval.
• Pull Test: Available according to project requirement → load value and test method must be confirmed by customer, shipyard, or class society.
• Certificate Requirement: Mill material certificate, test report, ABS approval / class inspection according to order scope → certificate availability is subject to project approval procedure.

How It Works

Mooring line or wire approaches the single bitt → The line turns around the smooth cast steel post → Coupling, checking, or mooring force is transferred through the cast body and welded base → Load is distributed into the reinforced deck structure according to vessel design

Applications

US inland river barges | Towboats and pushboats | Workboats | Small service vessels | Harbor craft | River mooring stations | Barge coupling and checking line handling | Newbuilding and replacement deck hardware projects

Certifications & Advantages

Certificates can be arranged according to project requirement, inspection scope, material traceability, and class society approval procedure.

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

Drawing & Photos

FAQ

Q1: How should a customer choose between thru-deck and flush-type single bitt bollards?

A1: The selection should follow the vessel deck arrangement. Thru-deck types are used where the bitt passes through or connects with deck structure below. Flush-type designs are used where the deck interface and underside clearance require a more compact welded arrangement. Final selection should be confirmed by deck drawing, reinforcement detail, and shipyard installation requirement.

Q2: Is ASTM A27-70-36 cast steel suitable for welding to barge or workboat decks?

A2: ASTM A27-70-36 is a cast steel material used for this type of deck hardware, but welding acceptance depends on the casting surface condition, weld-zone preparation, deck steel material, WPS, preheat requirement, and class or shipyard inspection rule. Welding procedure details should be confirmed before installation.

Q3: Does the supplied parameter table define the bollard SWL?

A3: No. The supplied table provides model descriptions, main dimensions, and weights. SWL, pull-test load, rope / wire MBL, deck reinforcement, weld size, and approval basis must be confirmed by project drawing or engineering calculation before they are used for selection or certification.