This plastic cap is affordable and will hopefully keep the water out of our diesel fuel. We currently use silicone to seal the diesel fuel cap. Apparently when they cut the cap for the key they left two spots, one at each end of the key grove that went right through. We found this after we had to have the fuel polished to remove the water. Most of the water was from rain. We added deck scuppers to help keep the cap above water where the water was forming on deck.
Beginning of July 2017 - Tied up in Marina Mazatlán, Mexico
We are currently house sitting in San Marcos, California (just North of San Diego).
And yet another part checked off the US buy list for the next cruising season.