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Presenting Flies Behind a Midstream Rock

by Philip Monahan
illustrations by Marshall Cutchin

Have a question you want answered? Email it to us at ask@midcurrent.com.

Question: What’s the best way to present a dry fly or a nymph to a fish holding behind a midstream rock? I have trouble getting any kind of good drift.

Pete C., Wellington, NZ

Casting Behind Midstream Rock

To cast a dry fly or a nymph to a midstream rock, position yourself downstream and to one side. Cast to the near-side “shoulder” of the rock (A), and drift the fly down the seam. Next, if possible, dap the fly directly behind the rock (B), and then drop it slightly downstream (C) to cover the V between the converging seams. Finally, move across stream and fish the far shoulder of the rock (D).

Answer: One of the first things a fly fisher learns is that trout like to sit behind rocks. (They also like to sit in front of rocks, but that’s another column.) The problem of presenting a fly to these fish is caused by the complex currents created by the rock. At the very least, the angler must contend with the river’s main flow, the faster seams along both sides of the rock, and the dead water or eddy behind the rock. Keep in mind that the fish is usually not sitting directly behind the rock, but slightly downstream, usually inside the V where the seams on either side of the rock converge. Your best bet for fishing a nymph or dry fly is to approach from downstream, so you won’t have to cast across as many conflicting currents.

Let’s start with a dry fly. You don’t want to cast your line directly over the fish, so if possible start downstream and slightly to one side of the rock. Try to get as close as you think prudent; in fast, choppy water, you can probably wade within 10 or 15 feet of your target, as long as you don’t throw a shadow over the lie. Make your cast to the “shoulder” of the rock, where the seam begins, and allow the fly to drift right down the seam. Don’t pick up the fly too early; allow the drift to continue below the rock for as long as possible. If you pick up too early, you may spook the fish. Plus, there’s always the chance that a fish is holding farther downstream.

At short distances, you can keep most, if not all of the fly line off the water by “high-sticking,” keeping your rod tip high. The less line you have on the water, the less chance there is for currents to ruin your drift. If you can’t wade within high-sticking distance, try a pile cast, which dumps your leader in a heap of slack around the fly. This slack lets the fly drift naturally for longer before drag on the fly line ruins the drift.

After you’ve made several drifts down the seam without a strike, cast to the broken water behind the rock. If you’re close, you can “dap” your fly in the eddy behind the rock, pick up, and then drop the fly in the downstream wash. Drift your fly through all the broken water inside the V created by the current seams on either side of the rock. If nothing happens, wade across and fish the far seam.

When possible, fish a dry-and-dropper tandem rig. Even when your dry-fly drift isn’t going well, the nymph below looks natural as it is buffeted by the currents. If you want to fish nymphs under an indicator, the same tactics apply, but you’ll want to cast farther upstream to give the nymphs time to sink. To drive the nymphs to the bottom, you can make a tuck cast, in which you stop the rod high on the presentation stroke, which causes the end of the line to swing downward, breaking through the surface tension more quickly.

MidCurrent Fly Fishing
 
Phil Monahan is a former Alaskan guide and was the long-time editor of American Angler magazine. He's now a columnist for MidCurrent and writes and edits the fly-fishing blog at OrvisNews.com.
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  • ltullis

    When fishing is tough in the flats I always test the pocket water. More opportunistic feeders there and you can approach them much closer without spooking them. Longer rods help fish pocket water by extending your reach while “High-Sticking”. 11′-15′ Tenkara rods by Tenkara USA or the 10-11 foot long 3-5 weight fly rods made by Sage, Cabelas, Greys, Temple Fork etc. are ideal. Shorter rods can be used too but the drape of the fly line will pull the fly out of the strike zone sooner unless you wade close to the target, which may not be possible due to spooky trout or heavy water. Also, wear camo clothing to blend in with surroundings.

  • QKSLVRNL

    Thanx for this Phil. Now, if only the rivers were open here

  • Henry

    On the upper Madison River from $3 Bridge to the outlet of Quake Lake, there are many spots with boulders that hold trout above and below them. The problem is that wading to them is impossible and they are too far to use some of the tactics that are outlined. At dusk there will be pods of trout feeding in these locations.

    As Phil mentions, any cast that land in the hydraulic cushion above the boulder or in the eddy water below is quickly dragged away by the faster water between the fly fisher and the target water.

    There are two possible solutions fro presenting a dry fly. On is to be able to place enough slack line on the fast water to delay the drag on the fly. I submit that this is virtually impossible at the speeds the currents are flowing. In the air mends, followed be on the water mends, simply do not work when the water is flowing at the velocity on the upper Madsion River.

    Plus as Phil mentions, the still water behind the boulders is actually not still. Often there are complex eddy currents that will create drag on any fly that lands without slack directly at the fly. Water may be going over the boulder or there may be two or more boulders with seams between them.

    The solution I have come up with is a cast that presents the dry fly with a huge amount of slack directly at the fly. The key concept is this – whether slack line is placed in the slower water beyond the faster water or that same slack line is placed in an upstream mend in the faster water, has virtually the same effect. The faster water takes the about the same time to pull the upstream mend downstream as it takes to pull that amount of slack line from the slower feeding lane. If you accept that concept, then the cast that places the greatest amount of slack will be the most effective.

    There are two casts I know of that are able to do that. Unfortunately, the nomenclature is confusing in that these two casts, although different, are most often called but the same name. The two casts are the puddle cast and the pile cast. Many if not most searches on the internet will describe these as identical casts.

    However, I consider a pile cast an actual cast and the “puddle cast” is really a downward mend of an upward directed cast. It “puddles” the line down onto the water and produces a ton of slack line and leader. It is a great cast in situations where you cannot predict the the direction of the mend such as when the leader will land in a whirlpool or any area of complex and conflicting currents.

    A puddle cast is not difficult cast. Basically, if you can do a reach mend, you can do a puddle cast. Think of it this way. In a reach mend you cast straight and mend the rod to one side. On a puddle, just angle that cast up and mend DOWN. It is a wonderful cast that solves a lot of difficult mends across varying current as long as there is open air above the run. The cast will collapse and the fly and leader will fall in a “puddle” with a huge amount of slack. The one place it does not work is where there are overhanging trees or bushes. But in open water, it a wonderful cast.

    Since you want most of the slack at the end of the cast, the best puddle cast is performed with an underpowered wide loop that collapses on itself. Think of a forward cast that collapses before it extends; angle that cast up and mend down. If you used too much power, shoot line to make the cast collapse.

    The second cast that will work if you are using a bushy fly is the pile cast. This is the same cast as the tuck cast but performed with a limber leader/tippet that cannot turn the bushy fly over. It is an overpowered cast that flips the end of the fly line over as in a tuck cast, but the leader cannot turn over the fly and the leader will collapse in a “pile.”

    The advantage of the pile cast over the puddle is that it will work in the wind and it is more accurate. The puddle cast cannot be used when there is wind that blows the underpowered cast and collapsing leader off track.