Marine Gooseneck Ventilator with Square Tube for Weather-Exposed Ship Decks | GB 4448 Type B

Marine Gooseneck Ventilator with Square Tube for Weather-Exposed Ship Decks | GB 4448 Type B

Product Overview

The GB 4448 Type B marine gooseneck ventilator is a square-tube ventilation terminal intended for installation on weather-exposed ship decks. Its curved hood changes the airflow direction and shields the duct opening from direct rain and sea spray while allowing natural ventilation or connection to a mechanical ventilation system. The Type B configuration uses a rectangular duct interface and covers nominal sizes 100 to 400 mm.

For engineering selection, the nominal size alone is not sufficient. The purchaser should confirm the rectangular duct opening, project-defined coaming height H1, deck position, airflow duty, closing arrangement, screen requirement, drainage, material, coating, and class or statutory requirements. The gooseneck geometry provides weather protection, but a weathertight, fire-rated, gastight, or vermin-proof function depends on the complete approved assembly and should not be assumed unless the required closure, gasket, screen, damper, installation detail, and test scope are specified.

Quick Specifications

• Product type: Square-tube marine gooseneck ventilator → rectangular duct terminal for natural or forced ship ventilation.
• Standard and type: GB 4448-1984 Type B → legacy dimensional configuration for drawing-matched, repair, and replacement projects.
• Nominal size range: 100 / 150 / 200 / 250 / 300 / 400 mm → covers rectangular duct openings from 120 × 80 mm to 460 × 290 mm.
• Project-defined height: H1 is decided by the vessel designer or purchaser → confirm deck position, coaming height, surrounding structure, and statutory requirements.
• Plate thickness options: 4 to 10 mm according to nominal size → affects structural stiffness, fabrication weight, and welding details.
• Approximate weight range: 21 to 244 kg from the supplied table → useful for handling, deck installation planning, packing, and freight estimation.
• Closure hardware: M12 clip / clamp arrangement with 1 to 5 pieces in the supplied data → exact component name, closing plate, gasket, and operating detail require drawing confirmation.
• Material and finish: mild steel, stainless steel, bronze, or copper options → final grade, joining method, corrosion compatibility, and surface treatment must be confirmed for each project.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm GB 4448 Type B square-tube configuration, nominal size, rectangular duct opening L × B, and whether the requirement is for newbuilding or replacement.

Step 2: Confirm the installation deck and project-defined H1. Provide the deck arrangement so the coaming height, weld interface, local reinforcement, hood orientation, and access for operation can be checked.

Step 3: Provide ventilation duty: air intake or exhaust, natural or forced ventilation, required airflow, connected fan data, allowable pressure loss, and any noise or insulation requirement.

Step 4: Confirm closure and protection details: clip / clamp arrangement, closing plate, gasket, drain, vermin or insect screen, weather shield, and approved fire or smoke damper interface if required.

Step 5: Confirm material grade and surface treatment. For non-steel construction, provide corrosion, joining, galvanic compatibility, polishing, and cleaning requirements.

Step 6: State quantity, certificate and inspection scope, applicable standard revision, vessel type, hull number, drawing or sample, delivery destination, and required delivery time.

Structure

Rectangular ventilation tube | Curved gooseneck weather hood | Project-defined coaming height H1 | M12 clip / clamp arrangement | Optional vermin or insect screen | Optional closing plate and gasket | Deck or duct welding interface | Marine surface protection

Ventilation, Weather Protection & Installation Advantages

• The square-tube Type B interface connects directly to rectangular ventilation trunks, reducing transition work where the ship duct arrangement is already rectangular.
• The downward-facing gooseneck hood reduces direct exposure of the duct opening to rain and spray. Final weather-tightness depends on the closure, gasket, drain path, welding, installation orientation, and acceptance test.
• H1 is intentionally project-defined in the supplied table. This allows the designer to coordinate the ventilator with deck position, statutory coaming requirements, nearby equipment, access, and the vessel’s ventilation arrangement.
• The bend radius and free opening area should be checked against the required airflow so the hood, screen, and closure do not create excessive pressure loss or restrict a connected fan.
• A removable vermin or insect screen can protect the ventilation opening, but mesh size and free area should be selected without unnecessarily reducing airflow. The screen does not by itself provide a fire rating.
• Drainage should be arranged so rainwater or condensate does not remain in the lower part of the hood or enter the connected duct. Drain detail is to be confirmed by drawing.
• For welded steel construction, fabrication quality should focus on dimensional control, smooth internal airflow surfaces, continuous weather-exposed welds where required, and coating access around clips, edges, and drainage points.
• Stainless steel, bronze, and copper versions require project-specific material grades and joining details. Their weights, thicknesses, and corrosion interfaces should not be assumed to be identical to the mild-steel table.

Custom Attributes

• Standard: GB 4448-1984 Type B → legacy square-tube configuration; confirm the contractual standard and drawing revision before production.
• Nominal Size: 100 to 400 mm → select together with the actual rectangular duct opening, airflow duty, and installation space.
• Duct Interface: 120 × 80 to 460 × 290 mm → key dimension for matching the ship ventilation trunk and deck penetration.
• Coaming Height H1: Project-defined → determine from deck position, vessel arrangement, statutory requirements, and approved drawing.
• Plate Thickness: 4 to 10 mm depending on size → use the selected configuration and material grade for final weight and welding confirmation.
• Closing Arrangement: M12 clips / clamps shown in supplied data → exact quantity varies by size; closing plate, gasket, and operating detail are to be confirmed.
• Screen Option: Vermin or insect screen available according to project requirement → mesh, material, removability, and free-area ratio should be specified.
• Material: Mild steel / stainless steel / bronze / copper → final grade and fabrication process are subject to approved project requirements.
• Surface Treatment: Sa 2.5 blasting and epoxy shop primer for carbon steel as reference → galvanizing, final marine coating, passivation, or polishing should match the selected material and vessel coating specification.
• Certificate Requirement: Available according to order scope → material traceability, maker inspection, class attendance, and test documentation must be agreed before quotation.

How It Works

Ventilation air enters or leaves the rectangular duct → Airflow changes direction through the gooseneck body → Downward-facing hood shields the opening from direct rain and spray → Screen blocks vermin or insects when fitted → Closing plate and clips secure the opening when closure is required → Water is discharged through the confirmed drainage path

Applications

Weather-exposed ship decks | Natural ventilation terminals | Mechanical ventilation duct inlets and outlets | Cargo and service-space ventilation subject to vessel design | Workboats and commercial vessels | Newbuilding projects | Repair and replacement to legacy GB 4448 drawings

Certifications & Advantages

Material documentation, dimensional inspection, coating records, closure checks, and classification society involvement can be arranged according to the approved drawing, project requirement, and agreed inspection scope.

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

Drawing & Photos

FAQ

Q1: Is the gooseneck ventilator automatically watertight or fireproof?

A1: No. The curved hood provides weather protection, but watertightness or weathertightness depends on the complete closing arrangement, gasket, welding, drainage, installation, and specified test. Fire resistance requires an approved fire damper or other compliant system component; it is not created by the hood or screen alone.

Q2: How should the project-defined H1 height be selected?

A2: H1 should be confirmed from the vessel deck position, Load Line and class requirements, required coaming height, nearby structure, access, and the approved ventilation drawing. It should not be selected only from nominal size.

Q3: Can GB 4448 Type B be used for a newbuilding project?

A3: It can be supplied when the contract or approved drawing specifically requires the legacy GB 4448 Type B dimensions. For new projects, confirm whether the shipyard requires a later CB/T configuration, current ventilation-accessory technical conditions, or a class-approved project design before placing the order.