Deck Welded Double Cross Bitt Bollard for Ship Mooring | GB/T 554 Type DH DN200–300

Product Overview

The GB/T 554 Type DH deck welded double cross bitt bollard is a welded steel-pipe mooring bollard with a high welded base for ship deck installation. According to the corrected size clarification, Type DH is the DN200–DN300 deck-welded configuration, mainly used for larger vessel mooring stations where direct welding to the deck structure and stronger load transfer into deck reinforcement are required.

Compared with the Type DL bolted-base version for below-DN200 sizes, Type DH focuses on welded deck installation, bevel-prepared fabrication joints, and a high base interface. The horizontal cross pipe is continuous through the double-bitt structure, which supports strength continuity and load transfer. Pipe-to-base joints and base-to-deck welding should follow the project drawing and WPS; rope-contact welds should be ground smooth to reduce damage to mooring ropes.

Quick Specifications

• Product type: deck welded double cross bitt bollard → high-base welded installation for ship mooring decks.
• Standard and type: GB/T 554-2008 Type DH → deck-welded high-base version of the double cross bitt bollard.
• Nominal diameter range: DN200–DN300 → separated from the Type DL bolted-base range below DN200.
• SWL range: 72–185 kN → used for initial bollard selection with deck reinforcement and rope lead direction review.
• Construction: welded steel pipe and steel plate → steel plate can be rolled into pipe and welded, or steel pipe can be used as specified.
• Welding focus: bevel preparation and deep-penetration welding at key joints → final weld detail, WPS, and inspection scope follow project requirement.
• Rope-contact finishing: welds and sharp edges dressed smooth → helps protect mooring ropes during wrapping and load transfer.
• Surface treatment: Sa 2.5 blasting + epoxy shop primer as reference → final coating, galvanizing, stainless polishing, or special finish according to order.

Main Technical Parameters

Main webpage dimensions for GB/T 554 Type DH deck welded double cross bitt bollard, limited to DN200–DN300. Dimensions are in mm unless otherwise stated.

Note: Deck weld groove, weld size, WPS, NDT scope, and deck reinforcement are project-specific and should be confirmed before production.

Selection & Inquiry Guide

Step 1: Confirm GB/T 554 Type DH and nominal diameter DN200–DN300 according to SWL and vessel mooring layout.

Step 2: Confirm deck welded installation, base height, available deck space, rope lead direction, and surrounding reinforcement.

Step 3: Confirm welding requirement: groove preparation, deep-penetration weld detail, WPS, weld inspection, and class witnessing if required.

Step 4: Confirm material requirement: mild steel, C-Mn steel, stainless steel, or special steel for ice-class projects if specified.

Step 5: Confirm surface treatment: shop primer, final paint system, galvanizing, mirror / satin polished stainless finish, or other specified finish.

Step 6: Confirm certificate scope before order: maker certificate, material certificate, class certificate, witness inspection, or project-specific approval.

Step 7: Provide quantity, destination, required delivery time, installation drawing, deck foundation drawing, and reference photos if available.

Structure

High welded base | Deck weld interface | Two vertical pipe bitts | Continuous horizontal cross pipe | Bevel-prepared welded joints | Smooth ground rope-contact areas | Shop primer or specified finish

Deck Welding, Fabrication & Load-Transfer Advantages

• The high welded base provides a direct welded interface to the deck structure, which is important for permanent ship mooring stations.
• The DN200–DN300 size range positions Type DH for larger welded deck mooring points where a high-base foundation and stronger deck load transfer are required.
• The continuous horizontal pipe is not a short separated stub; it supports a more continuous force path across the double cross bitt structure.
• Pipe and base joints can be bevel-prepared before welding. Deep-penetration welding should follow the approved project drawing or WPS.
• Weld beads near rope-contact zones should be ground smooth after fabrication to reduce local rope abrasion during mooring operations.
• Type DH is differentiated from Type DL by welded base, DN200–DN300 size range, and deck welding requirements. It should not be represented with flat bolted-base photos.

Custom Attributes

• Standard: GB/T 554-2008 → reference for Type DH form, main dimensions, SWL, and weight.
• Type: DH → deck welded double cross bitt configuration with high base.
• Nominal Diameter: DN200 / DN250 / DN300 → corrected Type DH range for welded deck bollard arrangements.
• SWL Range: 72–185 kN → used for mooring bollard selection; it should not be mixed with rope MBL or lifting terms.
• Base Form: High welded base → intended for direct deck welding and load transfer into reinforced structure.
• Manufacturing Method: Welded steel pipe and steel plate → rolled plate pipe or steel pipe can be selected according to project requirement.
• Welding Control: Bevel preparation and deep-penetration welding where specified → final WPS, NDT, and inspection scope to be confirmed.
• Rope-Contact Finish: Ground smooth welds and burr-free surface → helps reduce rope damage at contact locations.
• Certificate Requirement: Available according to project requirement → class approval and inspection scope should be confirmed before quotation.

How It Works

Mooring rope is led to the bollard → Rope is turned around the double-cross bitt structure → Continuous cross pipe and smooth contact surfaces support rope load transfer → Welded high base transfers local force into the reinforced deck structure → Final inspection and coating are completed according to project requirement

Applications

Cargo ships | Tankers | Bulk carriers | Container vessels | Larger workboats | Deck mooring stations | Newbuilding welded deck projects | Replacement of DN200–DN300 welded-base bollards

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: Why should Type DH have a separate webpage from Type DL?

A1: Type DH is the deck welded high-base version covering DN200–DN300 according to the corrected clarification. Type DL is the bolted flat-base version for nominal diameters below DN200. The installation method, size range, photo requirements, and SEO intent are different.

Q2: What welding information should be confirmed for Type DH?

A2: Confirm groove preparation, weld size, WPS, weld inspection method, deck reinforcement, and whether class witness inspection is required. These items should follow the project drawing rather than being assumed from the standard table alone.

Q3: How should the correct DH nominal diameter be selected?

A3: Select DN200, DN250, or DN300 by required SWL, vessel mooring arrangement, rope lead direction, deck space, deck reinforcement, and class requirement. For replacement projects, provide the existing bollard drawing or photos to avoid selecting the wrong base type.