Narnia is a Caliber 40 LRC (Long Range Cruiser) and as such she is capable of carrying about 212 gallons of diesel fuel in her 2 tanks. As we spend most of our time sailing, not motoring, we tend to not use a lot of fuel. This becomes an issue as the fuel in the tank ages it can begin to collect water that will allow filter clogging "gunk" to grow. One of the ways to combat this is to polish the fuel to remove the gunk before it can clog the fuel filters at the most inopportune time.

Today we spent about 4 hours pumping Narnia's fuel though a set of 2 micron Racor filters (pumped it from one tank to the other and back). We currently only have about 75 gals of fuel aboard so we would pump one tank dry, clean it, then pump the other tank dry and clean it.

Given that the fuel in the tank is probably 15 years old, I was surprised by how little gunk and water was actually present. It helps that the tanks are low in the bilge and that bay water temperature is cold.