Feeding Slack on Fast Water

Feeding Slack on Fast Water

When a downstream delivery is just the thing.

  • By: David Hughes
  • Photography by: David Hughes
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We all know that downstream presentations and feeding slack are necessary when fishing dry flies over snotty trout, those fish poking their noses out to sip small mayflies, caddis or midges on the smooth flats of such heavily-pestered waters as the Missouri in Montana, the Hiwassee in Tennessee, the Delaware in New York or Pennsylvania, and on and on, almost everywhere. If you fish such situations with upstream casts you show your line and leader to trout before they ever have a chance to examine your fly. You know what they do then. That’s why you take your position at an angle upstream from them, and make your casts downstream to them, laying excess slack line on the water and feeding it into the drift as needed to keep the fly floating freely, ahead of the spooky line and leader.

That is smooth water, where it sometimes seems a downstream cast, with slack fed behind the fly, is the only solution. Trout in fast water don’t have the same opportunity to see your line in the air or your leader on the water, and they don’t operate at a pace that allows leisurely examination of any fly, surface or sunk. So the downstream cast is deemed of little use, and seldom applied, on fast water. That can be a mistake that costs you chances at trout.

As an example, I camped on the lower end of Rock Creek, in Montana, last season not long after runoff. While sitting in a lawn chair alongside a swift run, the first evening just after dinner, I raised my always-handy miniature Nikon binoculars and spotted trout rising rather snappily along the far bank, where the water slowed a bit. On closer gander, I also saw a few light-colored caddis adults flitting in the air, and occasionally dancing on the surface to shake off their eggs. This was fatal behavior. Those trout were nipping at them, occasionally sending spurts of water into the air as punctuation to the endings of little lives.

The situation looked like an easy one to solve. I slipped into waders, knotted a size 14 Elkhair Caddis to 5X tippet, and navigated a difficult crossing to within 30 feet of that far bank before many more caddis died. I turned upstream to begin catching trout and instantly bumped into a dilemma: The current, so soon after runoff, could be crossed, but it was still too pushy to wade against. I couldn’t make any progress upstream. The bank was far too tree- and brush-choked to have any hope of fishing from shore. That left only one direction for any further navigation: downstream.

I was able to make enough casts, from the single position I’d attained, to establish that the Elkhair was what they wanted, and that the fish, browns at 12 to 14 inches, were worth some struggle to catch. Then I turned and let the current thump my butt downstream, putting on my brakes every 20 feet or so, wherever a backeddy behind a boulder let me get some traction, plant a stance. Then I’d cast at an angle downstream, wiggling the rod as the line loop unfurled in the air, and at the same time laying the rod over upstream, to position it behind the line after it landed on the water.

These slack-line casts that allow you to feed line into a subsequent drift are often combinations of more than one rod movement at the same time. Some of them might sound complicated in the description—a downstream wiggle cast overlaid with a simultaneous cross-stream reach cast—but on the water you learn to just do what the shape of the current requires to give your fly a free float. With a bit of experience it all gets pretty simple. Your brain doesn’t even pause to calculate it; your arm does what needs to be done, with no complicated descriptions attached. You wiggle your rod to form S-curves when it lands. You tip it over upstream at the same time so you can follow those curves as they straighten. Both movements combine to give your dry fly from 10 to 15 feet of free float down that charging water. No cast description required.

It takes no further education to hold some slack in your line hand, behind the first guide, and to lay this onto the water to follow the fly as it floats downstream. You feed the slack with your line hand, toss the rod tip forward to lay the slack onto the water. Or you can repeat the motions of the cast you just made, wiggling the rod tip briskly so that slack line is drawn through the guides and lands in S-curves on the water. This slack trots along behind the fly and leader and line that are already headed downstream, extending your drift another five to 15 feet, or at times even 50 feet. In other circumstances, usually on a big river where I’m rooted to a position atop a boulder or in an anchored boat, I’ve been able to deliver a hook to a hungry trout 100 feet beyond the distance I was able to cast.

It has happened fairly rarely, but I’ve set successfully against trout so far away that my backing knot was far beyond the rod tip. Two codicils qualify this. First, you must delay the hook set a fraction of a second on any presentation made downstream, and second, you are less and less likely to get the hook set into a trout that takes a fly as it drifts farther and farther beyond 60 feet or so from the rod. That’s all right; it’s hellish fun to draw a rise out of a trout so far away that few other folks would even bother attempting to show it a fly.

But back to that night on Rock Creek, where my caddis imitation rarely got farther than 50 feet from me, and I was able to set the hook into far more than half of the trout that rose to take it. In the short time before darkness forced me to wade back across the river to that lawn chair, I’d danced perhaps 20 trout.

Lots of stream situations can be improved by fishing dry flies downstream, then feeding slack either to get a drag-free drift where you otherwise could not, or showing the fly beyond the distance a normal cast could reach. Wading difficulty is often the deciding factor, as it was for me on Rock Creek. Many riffles are too big to wade upstream, but it’s easy to insert yourself at the upper end, let them ease you along while you fish them downstream. Some pocket water on medium to large rivers can be approached from only a single direction; if that happens to be upstream, then you need to fish it by feeding slack downstream. Many ledges cut across streams of all sizes, forming broad swaths of lined-up lies that you can wade above, and fish only by feeding slack into downstream drifts over all those lies below the ledge.

I could go on and on, listing dryfly water types that are most productive when approached from upstream, and fished best with downstream casts and slack-fed drifts. But you’ll quickly learn to sort these situations out for yourself, once you spend the brief bit of time it takes to practice inserting slack into your cast while the line is in the air, and more slack into your drift after the line has landed on the water.

The usefulness of inserting slack line into downstream drifts on fast and somewhat rough water is far from limited to dry flies. When trout feed just subsurface, you can show floating flies to them all day and catch little but refusals. Instead, drift nymphs, wet flies or sunken emergers downstream to them, in the same way you might fish the dries, and trout are much more likely to take them. The one sure way to make a success of this operation is to tie a small yarn or soft indicator into your leader three to six feet from your submerged fly. Then feed slack behind that indicator just as if it were a dry fly. If you see it hesitate, dip or otherwise move contrary to the current, set the hook. Something is almost certain to be out there.

It’s at least as useful to feed slack into the drift of a nymph, or a brace of them, rigged for the standard split-shot-and-indicator tactic. Your presentation is almost always made upstream, on a short cast. Then it takes about half of a drift for the nymph to reach the bottom and begin fishing as it should. If you lift it off the water for the next cast just when it comes abreast of you, the length of bottom successfully probed for trout is unnecessarily restricted. Instead, as the indicator passes your position, turn to follow it. Lower your rod tip and follow the indicator to let the nymph tumble freely downstream along the bottom to the extent of the line that you’ve originally cast. You could let the current lift your nymph off the bottom, and trout will often take at that moment. But why stop there?

If you carry some slack in your line hand and feed it out through the guides as the indicator continues to drift downstream, you can extend the useful length of your presentation, on each cast, as far as you dare, or as far as the shape of the water allows. As with dry flies, I’ve taken trout downstream more than the length of the fly line by feeding slack into a drift of a pair of nymphs. A similar set of codicils applies to the nymph, though in this case you never want to delay setting the hook if you see your indicator move. Your chances of hooking a trout decrease dramatically as you extend line into a nymph drift longer than about 50 feet. Perhaps the most important instruction: Never use an extended drift as a lazy way to fish water you could move into position to fish with shorter casts. Use it only to cover water you could never cover otherwise.

Dave Hughes’ latest book is Pocketguide to Western Hatches.