"I'd be surprised if more than 10% of recreational and commercial craft meet New Zealand's obligations under MARPOL 73/78 for oil in bilge water discharge,” said Mike Harris, MD of Lighthouse Marine Equipment.

MARPOL 73/78 [International Convention for the Prevention of Pollution from Ships] limits oil in discharged bilge water to a maximum of 15ppm. A single drop of diesel in a litre of water amounts to 40ppm.

"Even careful boat owners end up with traces of fuel, oil, grease and hydraulic fluid, as well as other engine room chemicals, in the bilge, where it mixes with water. It's unavoidable,” explains Harris.

In some cases, bilge water carries a heavy load of pollutants, all of which are discharged into the water every time the bilge pump is used. Such pollution can be especially damaging in crowded and/or enclosed anchorages, marinas and sensitive ecological areas.

Lighthouse Marine Equipment has the solution.

Easy to maintain and monitor, WAVEstream bilge water filter systems address oil in bilge water, removing it using highly efficient filter cartridges able to cope with a wide range of water flows.

WAVEstream filters are simply installed between the bilge pump and water outlet, ensuring only clean, oil-free water is pumped overboard.

Four WAVEstream models are offered, suitable for craft ranging from large commercial vessels to small day boats. There are different grades of filter depending upon the application and all WAVEstream bilge water filter systems are Lloyds Register of Shipping approved.