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Marine Ventilation 

CFW designs, supplies and installs fans and ducting for marine ventilation. Fan accessories such as louvers, shutters and cowl vents are also available. Standard components as well as custom solutions are available.

For safety reasons and to conform to regulations, boats and ships require sufficient ventilation. Before an engine is started, and especially after refuelling, it is critical to remove fuel potentially explosive fumes. Since the petrol vapours are heavier than air, they will settle in bilge areas and must be removed using a blower, to be operated for at least four minutes before starting up. There should also be fuel fume sensors designed for marine use in enclosed spaces to ensure safety.

Engine room ventilation may keep the space at negative pressure when passenger areas are adjacent to the room or at positive pressure, which has the advantage of preventing dust from entering. Engine rooms may need ventilation air both for cooling and for combustion.

In the case of passenger areas, ventilation is needed to provide fresh and clean-smelling accommodation and prevent carbon monoxide poisoning. Any kind of petrol use or stove, especially where there are fuel leaks, can potentially introduce carbon monoxide into the boat. Ventilation also helps to control mould, mildew and corrosion. A combination of cabin fans and passive vents can make the trip safer for the crew and passengers.

To comply with these requirements, a minimum of two ventilator ducts need to be installed. Larger boats will require more. While passive or natural ventilation can be used while the boat is running, ventilation systems will still need to be powered before the engine is started. For marine ventilation, the possibility of taking in water through vents also needs to be taken into account, especially for engine air inlets. Louvered vents made of stainless steel or plastic may be used for the latter application. Cowl vents are a popular and reliable option, especially Dorade boxes (sometimes called simply “dorades”), which are designed to permit air to enter while keeping water out.

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Cape Town, South Africa (HQ)

3 Parin Road, Parow Industria, 7500, Western Cape

Johannesburg, South Africa

4 Chilworth Road, Founders View North, Modderfontein, Edenvale, 1645, Gauteng


Cape Town, South Africa (HQ)

T +27 (0)21 931 8331
F +27 (0)21 931 3165

Johannesburg, South Africa

T +27 (0)11 452 5830 / 5146
F +27 (0)11 452 5132


Cape Town, South Africa (HQ)

 Johannesburg, South Africa

Mailing address:

P.O. Box 1542, Parow, 7499, South Africa