Quick-Action Weathertight Steel Hatch Cover | CB/T 3728 Type C for Ship Deck Access

Quick-Action Weathertight Steel Hatch Cover | CB/T 3728 Type C for Ship Deck Access

Product Overview

The CB/T 3728 Type C quick-action weathertight small steel hatch cover is a hinged ship-deck access closure with a gasketed cover, central operating linkage, and wheel handles on both sides. Turning either handwheel drives the perimeter dogs to compress or release the gasket, allowing the hatch to be operated from the deck side or the space below. A spring-assisted hinge reduces handling effort when correctly adjusted.

The supplied range includes square and round configurations with nominal sizes 530, 630, and 830, clear openings of 500, 600, and 800 mm, and approximate cover weights from 42.2 to 85.1 kg excluding the hatch coaming. When the hatch is intended for an emergency escape route, the clear opening, operating access, quick-action mechanism, opening direction, hold-open arrangement, and classification approval must be confirmed for the actual installation. CB/T 3728-2011 was withdrawn on 12 December 2023; it should therefore be treated as a legacy, replacement, or project-specified standard, while newbuilding projects should confirm the applicable current

standard and class rules.

Quick Specifications

• Product type: quick-action weathertight small steel hatch cover → closes exposed deck access openings while allowing frequent manual operation.
• Standard and type: CB/T 3728-2011 Type C → legacy Type C arrangement with a central closing mechanism and operation from both sides.
• Shapes and nominal sizes: square 530 × 530 / 630 × 630 / 830 × 830 and round Ø530 / Ø630 / Ø830 → selection follows the vessel opening and access requirement.
• Clear opening range: 500 / 600 / 800 mm → square versions use rounded-corner openings; round versions use circular openings.
• Closing arrangement: handwheel-driven quick-action dogs with a spring-assisted hinge → supports rapid opening and uniform perimeter gasket compression.
• Cover thickness options: 4 / 6 / 8 mm in the supplied table → exact cover plate, coaming plate, and reinforcement details must match the approved drawing.
• Testing: chalk/contact test and hose test can be arranged according to the approved inspection plan → test method, acceptance criteria, and witnessing scope are confirmed before production.
• Materials and finishes: mild steel or stainless steel; blasted and primed, polished, galvanized, or project-specific finish → coating compatibility with hinges, dogs, spindle, and gasket seating must be checked.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm CB/T 3728 Type C, square or round shape, nominal size, clear opening, and whether the order is for newbuilding or legacy replacement.

Step 2: Confirm installation purpose: normal deck access, machinery/store access, or emergency escape route. Escape use requires project- and class-specific confirmation.

Step 3: Provide deck position, required coaming height, surrounding deck thickness, reinforcement arrangement, opening direction, and available operating space on both sides.

Step 4: Confirm material, cover plate thickness, coaming plate thickness, hinge and dog material, gasket grade, surface treatment, and corrosion environment.

Step 5: Confirm inspection scope: dimensional inspection, mechanism operation test, gasket contact/chalk test, hose test, material certificates, maker certificate, and class witnessing if required.

Step 6: Provide quantity, vessel type, classification society, approved drawing or reference photo, delivery destination, and required delivery time.

Structure

Steel hatch cover | Central quick-action linkage | Inner and outer handwheels | Perimeter dogs | Spring-assisted hinge | Gasket and compression seat | Welded hatch coaming | Hold-open / securing arrangement to project requirement

Closing, Sealing & Installation Advantages

• The central operating linkage moves multiple dogs from one handwheel position, reducing the number of separate cleats that the operator must secure around the cover.
• Operation from both sides supports access control from the exposed deck and the space below; for escape service, both operating positions must remain unobstructed and readily accessible.
• Perimeter dogs distribute clamping around the gasket seat. Correct dog adjustment and an even coaming landing surface are necessary for consistent gasket compression.
• The spring-assisted hinge can reduce manual opening effort, but spring setting, hinge alignment, cover balance, and a reliable hold-open arrangement must be verified during installation.
• Square clear openings use rounded corners in the supplied data, helping avoid sharp internal corners and supporting a practical passage geometry.
• The hatch is weathertight, not automatically watertight or fire-rated. Any watertight, A-class, B-class, or escape-specific requirement needs separate design evidence and approval.
• The welded coaming transfers local cover and operating loads into the deck structure. Deck cut-out, coaming welds, local reinforcement, drainage, and corrosion protection should be reviewed by the shipyard or design office.

Custom Attributes

• Standard: CB/T 3728-2011 → withdrawn legacy standard; confirm acceptance for replacement work or specify the current project standard for newbuilding.
• Type: C → quick-action hinged small hatch with a central securing mechanism and operation from both sides.
• Shape: Square / Round → select according to deck opening geometry and required clear passage.
• Clear Opening: 500 / 600 / 800 mm → confirm passage size, access route, and removal space for equipment or personnel.
• Operation: Inner and outer handwheels → allows opening and closing from either side when access is unobstructed.
• Gasket: Neoprene / NBR / high-nitrile option → final grade depends on weather, oil, temperature, and project compatibility requirements.
• Surface Treatment: Sa 2.5 blasting + epoxy shop primer, polishing, galvanizing, or specified coating → final system follows vessel coating and material compatibility requirements.
• Certificate Requirement: Available according to order scope → class inspection, test witnessing, and certificate type must be confirmed before quotation.

How It Works

Turn either handwheel → Central linkage rotates and moves the perimeter dogs → Dogs release or compress the gasketed cover → Spring-assisted hinge supports opening → Hold-open device secures the raised cover → Reverse the sequence to close and verify uniform gasket contact

Applications

Exposed deck access openings | Machinery-space and store-room access | Shipboard service passages | Emergency escape-route openings subject to approval | Newbuilding and replacement projects

Certifications & Advantages

Certificates and inspection can be arranged according to project requirement, material traceability, approved test scope, 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 this hatch cover watertight or fire-rated?

A1: No such rating should be assumed. The supplied product basis is weathertight. Watertight pressure resistance or fire integrity requires a separately approved design, test standard, and certificate scope.

Q2: Can the Type C hatch be used as an emergency escape hatch?

A2: It can be considered when the approved vessel arrangement requires a quick-action hatch operable from both sides. The clear opening, operating access, opening direction, hold-open device, securing arrangement, coaming height, and applicable class requirements must be confirmed before quotation.

Q3: Is CB/T 3728-2011 still a current standard?

A3: No. The official Chinese standard record shows that CB/T 3728-2011 was withdrawn on 12 December 2023. It remains relevant for legacy and replacement projects only when accepted by the customer and class. New projects should confirm GB/T 23426-2009 / ISO 5778:1998 or other applicable project and class requirements.