Weight, size and type of mooring are all variable, depending upon the bottom you''re mooring in and the waves you''re likely to get in that much breeze. Our mooring, designed to withstand up to 70 knts, must weigh about fifteen pounds; its a helical screw, fastened into a muddy/silt bottom. Our harbor is in a narrow, winding river, so there is no fetch for waves to build. Before the new setup, everyone here used mushrooms; up to 200 pounds for 50'' boats. I''ve heard of other types of anchors - including old car engines and big poured blocks of concrete being used as well. The best idea may be to see what people in your harbor use, and if it seems to work, go with that.