Marine Steel Weathertight Single-Leaf Door with Dogs Operable from Both Sides | GB/T 3477 Type A

Marine Steel Weathertight Single-Leaf Door with Dogs Operable from Both Sides | GB/T 3477 Type A

Product Overview

The GB/T 3477 Type A marine steel weathertight single-leaf door is intended for access openings in enclosed superstructures, deckhouses, companionways, forecastle spaces, and similar boundaries above the freeboard deck. The hinged door leaf closes against a continuous gasket, while multiple dogs or clamping devices compress the gasket around the frame to limit water entry under weather exposure.

“Dogs operable from both sides” means that the closing devices can be released and secured from either side of the bulkhead. It does not mean that the door leaf swings in both directions. The opening direction, sill height, installation position, surrounding bulkhead strength, and outward-opening arrangement are to follow the vessel drawing, Load Line requirements, and class approval. This page retains the customer-supplied GB/T 3477-2008 Type A size basis; new projects should confirm whether the current GB/T 3477-2023 edition is required.

Quick Specifications

• Product type: steel weathertight single-leaf hinged door → provides weather protection for external access openings above the freeboard deck; it is not a watertight subdivision door.
• Closing arrangement: multiple dogs operable from both sides → allows the gasket to be compressed and the door to be opened or secured from either side of the bulkhead.
• Standard basis: customer data follows GB/T 3477-2008 Type A → this edition has been withdrawn; GB/T 3477-2023 is the current national standard for new project confirmation.
• Clear opening series: 1200 × 600 mm to 1700 × 800 mm in the supplied schedule → select according to access, equipment passage, installation space, and approved ship arrangement.
• Material options: shipbuilding mild steel or stainless steel → final grades, welding consumables, gasket material, fasteners, and corrosion-isolation details are project-specific.
• Door outline: AF / AY variants are referenced in the supplied table → corner configuration, R80 detail, and bulkhead cut-out must match the selected drawing.
• Inspection: dimensional inspection, gasket-contact check, operational check, chalk test, and hose test can be arranged according to the agreed inspection plan and class requirement.
• Optional security: anti-piracy or internal locking device can be discussed → it must not conflict with escape, fire-safety, operational, or class requirements.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm the contractual standard and designation: legacy GB/T 3477-2008 Type A, current GB/T 3477-2023, AF or AY outline, clear opening H × W, hinge side, and opening direction.

Step 2: Provide the vessel type, ship length, installation boundary, deck level, Load Line position, sill or coaming height, surrounding bulkhead thickness, and available reinforcement.

Step 3: Confirm door-leaf plate thickness, stiffener schedule, frame profile, number and position of dogs, hinge arrangement, gasket section, and whether the door must normally open outward.

Step 4: Confirm material and corrosion protection: shipbuilding steel or stainless steel, coating system, hot-dip galvanizing if required, stainless fasteners, gasket material, and galvanic-isolation details.

Step 5: Confirm optional functions: anti-piracy locking, internal securing, padlock provision, hold-open device, kick plate, vision panel, fire rating, insulation, or access-control interface. Each option is subject to project approval.

Step 6: Confirm inspection and documentation scope: chalk test, hose test, operational test, material certificates, maker certificate, class witnessing, quantity, destination, and required delivery time.

Structure

Welded steel door frame | Single hinged steel leaf | Continuous weathertight gasket | Multiple dogs / clamping devices | Both-side operating handles | Hinges and pins | Door stiffeners | Hold-open arrangement | Optional anti-piracy lock | Coating or stainless-steel finish

Weathertightness, Installation & Quality Advantages

• Multiple dogs distribute compression around the door perimeter, helping the gasket maintain continuous contact with the frame when the door is correctly adjusted and secured.
• Both-side operation allows personnel to release or secure the closing devices from either side of the boundary without describing the door as double-acting or double-swing.
• The door frame, leaf plate, and stiffeners are selected as one structural assembly. Final thickness and reinforcement depend on door size, ship length, exposure position, and the approved standard or class drawing.
• The installation opening and surrounding bulkhead require dimensional control before welding. Frame distortion during welding can reduce gasket contact and make dog adjustment difficult.
• Replaceable gasket, adjustable closing devices, serviceable hinges, and accessible lubrication points support inspection and maintenance throughout the vessel’s service life, subject to the selected design.
• For mild-steel doors, blasting, shop primer, and final vessel coating should be coordinated with the shipyard painting specification. Stainless-steel doors require grade, surface finish, weld treatment, and dissimilar-metal isolation confirmation.
• Quality control can include material traceability, welding procedure control, dimensional inspection, flatness and diagonal checks, dog engagement, hinge operation, gasket-contact verification, hose testing, coating inspection, and class witnessing according to the agreed inspection plan.

Custom Attributes

• Product Category: Marine weathertight door → for external access boundaries above the freeboard deck; not for watertight subdivision service unless separately designed and approved.
• Leaf Type: Single leaf, hinged → the leaf opens in one approved direction and is normally arranged to open outward unless otherwise accepted.
• Closing Method: Multiple dogs operable from both sides → provides distributed gasket compression and access to the closing controls from either side.
• Legacy Standard: GB/T 3477-2008 Type A → use when required for an existing vessel, replacement project, or contractual drawing based on the older edition.
• Current Standard: GB/T 3477-2023 → confirm for new projects because the 2008 edition is officially withdrawn.
• Opening Range: 1200 × 600 to 1700 × 800 mm in supplied data → select according to clear passage, equipment access, vessel arrangement, and approved drawing.
• Material: Mild steel or stainless steel → final grades and welding requirements must be confirmed; stainless substitution is not a simple material swap.
• Testing: Chalk test / hose test / operational test → test method, pressure, distance, nozzle, acceptance criteria, and witnessing follow the approved inspection plan.
• Security Option: Anti-piracy locking device → available only when compatible with emergency escape, fire protection, and vessel operating procedures.
• Fire Rating: To be confirmed → weathertight construction does not automatically provide A-class or B-class fire integrity.

How It Works

Close the hinged leaf against the frame → Engage dogs from either side → Dogs compress the continuous gasket around the perimeter → Gasket and frame limit weather-water ingress → Release dogs and open the leaf in the approved direction

Applications

Enclosed superstructures | Deckhouses | Companionways | Forecastle access | External accommodation access | Machinery-casing access above freeboard deck | Weather-exposed bulkhead openings | Newbuilding and replacement projects

Certifications & Advantages

Certificates and inspection witnessing can be arranged according to the contractual standard, class society, flag requirement, approved drawing, material traceability, and agreed inspection plan. Certificates are not automatically included with every supply.

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

Where fire integrity, watertight integrity, type approval, or statutory certification is required, the exact product configuration and approval scope must be confirmed separately before quotation.

Drawing & Photos

FAQ

Q1: What is the difference between a weathertight door and a watertight door?

A1: A weathertight door is intended to prevent water from penetrating the ship under weather exposure when properly closed. It is not automatically designed to withstand a continuous hydrostatic head or to serve as a watertight subdivision door. The required boundary function must be confirmed from the vessel plan and class rules.

Q2: Does “dogs operable from both sides” mean that the door opens both ways?

A2: No. It means the dogs or clamping devices can be operated from either side of the bulkhead. The hinged leaf still opens in one approved direction, normally outward for exposed Load Line doors unless another arrangement is accepted.

Q3: Should a new project specify GB/T 3477-2008 or GB/T 3477-2023?

A3: GB/T 3477-2008 may remain relevant for replacement doors or existing drawings, but it is officially withdrawn. GB/T 3477-2023 is the current edition. The shipyard, designer, owner, class society, and flag requirement should confirm the contractual edition before production.

Zhongyuan Ship Machinery Manufacture (Group) Co., Ltd. was founded in the 1990s and has developed into an integrated marine equipment manufacturer and project supply partner combining manufacturing, technical support, and export services. The group consists of four factories and one export trading company, with more than 300 employees, including over 20 experienced technicians and engineers. Our export company supports global customers with project communication, technical documentation, logistics coordination, and after-sales service.

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