Can't be just an issue of mass. This has to do with weight (which is different) and/or density. No matter what the mass is, if it's distributed such that the forces involved in maintaining surface tension aren't overcome...the fly will float. Even if the hook breaks the surface film it can still float if the total weight of the hook/feathers/fur/water absorbed by the fly is LESS than the weight of the volume of water displaced by the fly. Floatant helps...it keeps the fly from absorbing water (allows less weight distribution to bug and helps to maintain "exclusion" from the surface film).
>Then why to ships made of cement float? When you consider the simple fact >that any hook has enough mass to break the surface film. The foot print >must be large enough do distribute the mass so the surface film is not >broken
