To get a line on a fluke:
If an anchor is lost or foul you can get a line on the upper fluke in this way, if the water is not too deep: Feel for the fluke with a pole or, better, a piece of iron gas pipe. When found, rest the pipe end on the tip of the fluke. Then send a messenger of rope with slip noose, down the pipe or pole until it falls over the fluke and on the arm. Carefully haul it taut, using the pole to keep it from slipping off until firmly fixed. By this means you can get a back pull on an anchor and shake it loose if caught under a timber or rock.