kitchen sink faucet loose

[jpkelpe]

Every time we get to a campsite the kitchen sink faucet is loose, sometimes very loose. There is a washer underneath the faucet which is attached to the "flexible" pipe that is loose, I keep tightening it but the road vibrations seem to loosen it. (The faucet is supposed to be able to swivel so you can put water in either sink). Has anyone else had this problem and if so how did you fix it?