Three easy ways to get your fly in front of fish in deep water
#2 WEIGHTED LEADERS
If you want to fish deep with an unweighted fly, you can add weight to your leader instead, typically by crimping on some splitshot. Use shot made specifically for fly fishing, which comes in very small sizes. And avoid removable shot with fins, since it can make your leader twist and cause the fly to drift unnaturally.
Figuring out how much shot to use is mostly trial and error, but there are some guiding principles. Start with the smallest splitshot you think will work. You can easily add more, but sliding crimped shot off your leader damages the mono. (Being both cheap and conservation-minded, I keep any used weights and pry them back open at home.) Crimp on the shot 12 to 24 inches above the fly, bearing in mind that the extra distance lets the fly drift more naturally. If it’s too far, however, the fly won’t sink enough.
Splitshot rigs are very versatile, but they can be cumbersome to cast, and the leader has a tendency to hinge and tangle at the shot. Try to slow down and open up your casting stroke a bit, making it more of a lob, and keep the casts short. Long casts may look cool, but on a river, you rarely need to cast farther than 25 feet.