22 October 2025

Many boaters will recognise the distinctive ‘below decks’ odour encountered onboard.  It’s a combination of restricted ventilation mixed with hydrogen sulphide gas*.

H2S is a colourless, highly toxic, flammable and corrosive gas with a distinct ‘rotten egg’ smell.  It’s often created on board boats from the tank vents, especially from black water tanks when flushing toilets.  For some people, the combination of unpleasant odour with a boat’s motion can exacerbate sea sickness**.

There’s a solution now thanks to Wave International’s Waveair, which is designed to filter out bad odours expelled by holding tank vents.  Waveair uses a new and unique filter media that targets H2S eliminating the foul-smelling gas from the vent.  The activated carbon media has a highly porous structure, and when air passes through the carbon filter it traps the molecules from gases and vapours.  This solution is perfect for uses on boats because it is non-toxic, chemically stable and operates across a wide range of temperatures.   When the carbon filter is saturated, it is easy to replace ensuring on-going effectiveness of the Waveair system over many years.

The Waveair is a compact tube-shaped filter, available in two sizes.  The Waveair Micro is just 200 mm long, and the Waveair standard measures 430 mm.  Both models come complete with brackets and hose connections designed to fit to 16 mm, 19 mm or 25 mm connectors. 

The Waveair filter is installed into the vent line after the holding tank and before the outlet.  The sophisticated filter media inside the Waveair removes the organic compounds which create the foul smell.  Once installed, the Waveair will operate effectively for at least 12 months before requiring a filter change.  New replacement filter cartridges are available through Wave’s network of international distributors and dealers.

The Waveair products are very competitively priced starting from around £42.00 ex VAT for the Waveair Micro, and all models can be easily retrofitted into any design of sail or motorboat. 

*Hydrogen Sulphide is a colourless, highly toxic, flammable, and corrosive gas with a distinct "rotten egg" smell at low concentrations. It is formed from the decomposition of organic matter and is found in natural gas, petroleum production, wastewater treatment, and other industrial processes. H2S is heavier than air and can accumulate in low-lying areas, making ventilation and detection crucial for safety. Exposure can lead to severe health problems, including respiratory irritation, pulmonary oedema, and can be fatal at high concentrations, over 4ppm. 

**NOAA (National Oceanic and Atmospheric Administration) National Oceanic Service says of motion sickness that “a person’s symptoms can be magnified by strong odours”.