They shouldn’t! A floating fly line is made of a braided nylon core, onto which PVC is added as a coating. The specific gravity (SG) of nylon is 1.2 and the SG of PVC is 1.4. With those numbers the line should sink. So, why does it float? (For perspective; Aluminum has SG of 2.7 … Continue reading WHY DO FLOATING FLY LINES – FLOAT?