Steel Double Bitt Bollard with Narrow Base | GB/T 554 Type C Ship Towing

Product Specification

Steel Double Bitt Bollard with Narrow Base | GB/T 554 Type C Ship Towing Equipment

Product Overview

The GB/T 554 Type C steel double bitt bollard with narrow base is a compact welded steel bollard for ship mooring and towing arrangements where the deck layout requires two vertical bitts on one common base plate. It is mainly used on small vessels, inland waterway vessels, workboats, boats, and other compact shipboard mooring positions where the bollard footprint, deck reinforcement, and rope lead direction need to be checked together.

This page is prepared according to the supplied GB/T 554-2008 Type C data for nominal diameters 50 to 150 mm and SWL values from 13 to 43 kN. Public standard information indicates that GB/T 554-2023 has replaced GB/T 554-2008 and is related to welded steel bollards for sea-going vessels; therefore, the applicable project standard, old-standard replacement need, and whether the latest GB/T 554-2023 or ISO 13795:2020 should be followed must be confirmed before final quotation.

Quick Specifications

• Product type: Steel double bitt bollard with narrow base → compact two-bitt arrangement for shipboard mooring and light towing positions.
• Standard and type: GB/T 554-2008 Type C according to supplied data → suitable for replacement or projects that still specify the older Type C narrow-base designation.
• Nominal diameter range: 50 / 75 / 100 / 125 / 150 mm → suitable for small and compact deck arrangements rather than large ocean-going mooring stations.
• SWL range: 13 to 43 kN → use only as the supplied safe working load table; towing load direction and deck support still require project confirmation.
• Construction: one base plate with two bollard bitts and reinforced connection → helps distribute rope force into the deck through a compact base arrangement.
• Main dimensions: A, b, B, D, D1, h, h1, H, L, r, and t → used for webpage drawing, deck-space checking, and quotation confirmation.
• Material options: C-Mn steel, stainless steel, and special steel for icebreaker projects → exact grade and certificate scope should be confirmed before production.
• Surface treatment: Sa 2.5 blasting + one layer epoxy shop primer as reference → polished, galvanized, or customized finish can be discussed when required.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm GB/T 554 Type C steel double bitt bollard with narrow base and nominal diameter 50 / 75 / 100 / 125 / 150 mm according to vessel drawing.

Step 2: Confirm whether the project is an old-standard replacement based on GB/T 554-2008 or a new project requiring GB/T 554-2023 / ISO 13795:2020 review.

Step 3: Confirm mooring or towing duty, rope size, rope lead angle, intended load direction, nearby chocks or fairleads, and whether the bollard is used for normal mooring or towing assistance.

Step 4: Confirm deck installation interface: base footprint, weld detail, deck plate thickness, local reinforcement, available clearance, and shipyard installation method.

Step 5: Confirm material requirement: C-Mn steel, stainless steel, or special steel for low-temperature / icebreaker service if required.

Step 6: Confirm surface treatment: shop primer, final coating system, galvanized finish, mirror / satin polished stainless steel, or other project coating requirement.

Step 7: Confirm certificate scope before quotation: maker certificate, material certificate, class certificate, weld inspection, NDT, witness inspection, or other project requirement.

Step 8: Provide quantity, vessel type, installation drawing, delivery destination, required delivery date, and reference photos if available.

Structure

Two vertical bollard bitts | Narrow common base plate | Reinforced connecting structure | Welded deck interface | Rope-contact head radius | Compact deck footprint | Painted or specified surface treatment

Welding, Load Path & Engineering Advantages

• Type C narrow-base construction provides a compact two-bitt arrangement where the vessel layout has limited deck space but still requires a standard double bitt bollard configuration.
• The common base plate and reinforced connection help transfer local rope force into the deck structure; deck reinforcement and weld detail should be checked by the shipyard or design office.
• The rounded rope-contact areas should be dressed and smoothed to reduce sharp local contact and avoid unnecessary rope wear during mooring or towing assistance.
• SWL should be treated according to the supplied GB/T 554 Type C table and the approved vessel mooring / towing arrangement; it should not be mixed with rope breaking load or test load.
• For replacement projects, the Type C narrow-base shape, overall length L, bollard diameter D, base width B, and height H should be compared with the existing deck arrangement before production.
• Material traceability, welding quality, dimensional inspection, coating inspection, and certificate scope can be arranged according to the agreed order and project approval procedure.
• Because public information shows that GB/T 554-2023 has replaced GB/T 554-2008, the applicable standard year should be confirmed before final datasheet release.

Custom Attributes

• Standard: GB/T 554-2008 according to supplied data → use for old-standard replacement or projects still specifying Type C narrow-base bollards.
• Latest Standard Check: GB/T 554-2023 to be confirmed for new projects → public standard information states that GB/T 554-2023 replaced GB/T 554-2008.
• Type: Type C narrow base → compact double bitt bollard with two bitts on one base plate.
• Nominal Diameter: 50 / 75 / 100 / 125 / 150 mm → select by vessel drawing, SWL table, rope arrangement, and deck space.
• SWL: 13 / 18 / 25 / 34 / 43 kN → use the supplied table and confirm load direction, deck reinforcement, and project approval basis.
• Material: C-Mn steel / stainless steel / special steel to be confirmed → final grade, low-temperature requirement, and certificate scope follow project specification.
• Installation: Deck welded → weld leg, base preparation, and deck reinforcement should be confirmed by approved drawing.
• Surface Treatment: Sa 2.5 blasting + epoxy shop primer as reference → final coating, galvanizing, or polishing follows customer requirement.
• Certificate Requirement: Available according to order scope → class inspection and certificate level should be confirmed before quotation.

How It Works

Mooring or towing line approaches the bollard → Rope is turned around one or both bitts according to the approved rope lead → Local rope force is transferred through the bitt body and reinforced base plate → Welded connection and deck reinforcement carry the load into the vessel structure → Coating and inspection are completed after installation

Applications

Small vessels | Inland waterway vessels | Workboats | Boats | Harbor service vessels | Compact deck mooring stations | Light towing assistance positions | Newbuilding and replacement projects

Certifications & Advantages

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

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

Drawing & Photos

FAQ

Q1: Is GB/T 554-2008 still the latest standard for this bollard?

A1: Public standard information shows that GB/T 554-2023 has replaced GB/T 554-2008. If the vessel drawing still specifies GB/T 554-2008 Type C, it can be reviewed as a replacement or project-specific requirement. For new projects, confirm whether GB/T 554-2023 or ISO 13795:2020 should be used.

Q2: Can the SWL table be used directly for towing?

A2: The supplied table provides SWL values for the Type C bollard. The actual towing or mooring use should still be checked against rope lead angle, load direction, deck reinforcement, weld details, and the project approval basis. SWL should not be mixed with rope breaking load or test load.

Q3: What information is needed before quotation?

A3: Confirm standard year, Type C narrow base, nominal diameter, SWL requirement, material grade, surface treatment, quantity, certificate requirement, deck installation drawing, delivery destination, and required delivery date.