The best saltwater fly fishing is usually below the surface especially when fishing in near shore or offshore waters. Fish like tuna, dorado, bluefish and stripers will often feed deep below the surface requiring the angler to get their fly deeper into the water column. This requires the use of a full sinking line or sinking shooting head.
Full sinking line
Full sinking lines are rated Type I thru V, with Type I being the lightest and V being the heaviest. For instance if you are fishing to fish only a few feet below the surface a Type I or II shooting head would work fine. However, if the fish are feeding 20 feet below the surface the Type V would be your line of choice. The entire fly line is weighted and is approximately 100 feet long. Once you learn how to cast these lines you’ll find that they are a good choice when fishing deep.
Integrated sinking shooting head
These are my favorite sinking fly line to use. The first 26 feet of these lines are weighted and the rest of the fly line is a mono core running line. Due to the slick surface of the mono core running line these fly lines cast like a dream. Additionally, since all the weight is loaded at the front end of the fly line the momentum of the weighted section helps extend the distance of your cast. These lines are rated in grains from 150 grains to 800 grains; 150 being the lightest and 800 is the heaviest. An 800 grain line will work most effectively to fish to 30 feet.
Lead core line
In depths over 25 feet the lead core line is a great choice. These lines work great when fishing from a drifting boat and when you’re dealing with strong currents because they sink so quickly. They are typically 20 feet in length and are attached with a loop-to-loop connection to a monofilament running line. The weight of the lead core line and the thin diameter of the monofilament running line allow these lines to get down faster when compared to the other types of sinking fly lines. However, they can be difficult to cast and the monofilament running line has a tendency to coil while casting.