Attwood Tsunami Mk2 500 GPH Manual Bilge Pump The Tsunami Mk2 is the most reliable Manual bilge pumps Attwood has ever designed. The patented X-Air impeller is engineered to to force air bubbles trapped in the hose and underside the pump out of the pipework. This prevents the pump from running dry which can damage the bilge pump. This pump is suitable for freshwater applications. Easy to install, the Tsunami Mk2 features external mounting feet which means you dont have to remove the basket when