Explaining an Airlock in a Bilge Hose - Rule Bilge Pumps

We get several calls about one of our bilge pumps that runs but won't pump the water out of the bilge. We'd typically ask if there was any sags or valleys in the bilge hose that could cause an airlock or water trap. We decided to put together this cool video that shows the affects of water trapped in a "valley" of a bilge hose.