The other night my dock lines were driving me up a wall and I remembered this thread
I tried WD40 as a quick fix and it worked great! I don't think it's just the chafe around the chocks (I have line protectors), but just that the whole line is creaking. . .things are stiff as wire, probably time to soak and wash
There was a direct correlation between length of line treated with WD40, and reduction in noise. . .