anchoring - page 7
5.7 Trip line
A trip line is simply a rope with a buoy tied to the crown of the anchor (photo 5.7.1). If your anchor is caught on something like a rock, someone else’s chain or even a cable, all you need to do is pull on the trip line to free your hook. We do advise adding a weight, although it is not very important, to the rope a few feet below the buoy to ensure that nobody catches it in their propeller (photo 5.7.2). The buoy also serves to mark the spot where your anchor is. This is particularly useful where you would fear that another boat might drop their anchor right on top of yours. We have found this feature so beneficial, that we almost never drop our hook without a trip line attached.
Note: If you can't find a buoy alternatively you can use one of your boats fenders.