This weekend, I highlighted one of my favorite stillwater patterns, the Little Fort Leech. One of the materials on that pattern is a shiny gold bead. Beyond that the pattern is unweighted but that bead does allow the pattern to break the surface and start a descent, nose first because of the bead. The retrieves will cause the fly to undulate in an up and down swimming motion. Not to be discounted is the marabou tail.
But, there are times where one is fishing shallower water. The fish are up onto the shelf/shoals and feeding. The weeds are a factor. It can be problematic if the fly dives too quickly beyond the feeding fish and gets hung up. Now the ubiquitous Intermediate Line (1.0-1.5 IPS) will eventually reach bottom, but the intent of the line is a slow descent and you may also want to use a fly pattern that is not weighted (bead head or wire wraps around shank). I would advise tying patterns for deeper/faster descents. If you only weight your flies around the shank, some suggest a unique colored tying thread for weighted patterns to differentiate them beyond their feel in the palm of your hand…say red thread head etc.
But, also tie unweighted flies that sink slowly and travel on a more horizontal plain. These unweighted flies will provide a slow descent when fish are feeding in shallow waters. If a bead must be used, perhaps go to a much smaller bead.
When you cast out a larger, unweighted fly, it may lay atop the surface weighting for the weight of the slowly descending fly line to pull it beneath. This creates an unnecessary downward bow in the line. I suggest taking the fly in your fingers and swishing it in the water, squeezing it and saturating the materials. Then cast it out. Give the fly a smart tug and it will usually break the water’s surface tension and sink…slowly sink in the higher zone for longer exposure to the fish.