**NOTE** This is Part Four in a Troutbitten Short Series about weights and measures. You can find the full series at the link below.
You can fish your whole life without thinking specifically about the weight of the flies on your line or their resistance to the air and water. You can also obsess about the details of your rig to the point where too many unanswered questions become obstacles — until you’re paralyzed with uncertainty.
Knowing your weights and measures and understanding how they interface starts with a simple awareness of things like leader length, material diameter, fly weight and distance to the target.
By considering the composition of the rig in your hands, questions form. Is the tippet diameter thick enough to turn over a #12 Parachute Adams? You must fish it to find out. It’s the only way.
What follows is the final installment in the Troutbitten short series, Know Your Weights and Measures. This finale focuses on the flies. I’ll provide examples of my flies and solutions below, but you must go into your own fishing with an open and curious mind. Because your fly rod, line, leader, tippet, casting stroke, river and water conditions are different than mine. I’m sure of it.
The distance from your target and the length you are casting is a knowable stat. And understanding that you are tight lining a nymph at twenty-five feet, for example, is an easy bit of knowledge to factor in. Things get more complicated when considering leader composition, but balancing power and turnover with length and material stiffness gets you out of the starting block.
So now, with some understanding of the accompanying elements, let’s think about the flies.
Fly Size and Material Resistance (Dries)
Fly size is basic knowledge that most anglers pick up quickly. Not only is it easy to communicate to fellow anglers that trout were taking a size #14 CDC Caddis this morning, we also learn what tippet diameter and length matches with each fly. (5X nylon is a good start with that #14 caddis.)
Knowing these stats makes the next adaptation easier . . .
Hours later, the action changes when Hendricksons start popping through the surface. Rising trout suddenly ignore the caddis, so it seems a #14 Hendrickson in a parachute style could be the ticket. The fly size here might be the same as the morning caddis, but the material resistance differs greatly. A parachute style grabs the wind and holds the fly back as the casting loop unfolds, while the tent-style, v-wing of the caddis cuts through the air. Tippet adjustment is therefore necessary to get the same turnover and the same s-curves built into the leader, resulting in a continued drag-free presentation and more trout at the end of the line.
With the Parachute, I’d likely shorten the 5X about a foot, then cast it to see if the change worked as expected.
Later in the evening, when trout find the Blue Winged Olive spinners, I might cut the 5x back another foot and add three to four feet of 6X nylon to cast the small olive spinner that has very little air resistance.
Importantly, it’s not just the size of the fly we must consider. It’s how the fly cuts through the air on delivery. And that material resistance matters in the water just as much as it does in the air. Let’s get to that . . .
Fly Size and Material Resistance (Underneath)
A Perdigon is the modern example of a nymph with limited resistance. Having no dubbing, chenille, hackle or legs to slow its descent, a Perdigon slices through the water column better than any other fly in my box. But sometimes, such a fly is not the best choice. And I often use Walt’s Worms, with their shaggy dubbing, as a slower-dropping option to match the size and weight of the fly I want to use.
Streamers should be given similar consideration. The deer hair head on my favorite Bunny Bullet Sculpin does not slice through the water. Instead it pushes water ahead of it on each strip, each jig or pulse. By contrast, a Half Pint streamer, in the same size, cuts through the water more than it pushes. It swims differently, and this contrast can literally be felt in the rod hand.
Material resistance vs weight is another balancing act on the water. Consider again the Perdigon vs the Walt’s. Without changing anything about my leader or presentation, I know the #14 Walt’s will sink at the same rate as the #16 Perdigon, from my fly box. And when I want to be deeper, quicker, I can choose a heavier fly or one that cuts through the water with ease — sometimes both.
We must change flies with size, weight and material resistance in mind. And just like the other weights and measures in this series, there is no substitute for experimentation on the water. Trying things for yourself is the best way to gain knowledge. Test without bias. And often, the results are surprising.
I’ll focus here mostly on the weight of the flies, because I choose beadhead and weighted flies most often, for the extra contact and strike detection when no split shot is involved.
But this discussion translates also to drop shot rigging and standard split shot rigging. I do both on a regular basis. And there are some flies in my box, like eggs, worms and cress bugs, that just fish better for me without built-in weight. Sometimes the freedom of motion permitted to an unweighted nymph is more attractive and productive than the extra contact of using weighted flies.
Knowing the weight at the end of the line is an excellent way to take the next step as an angler. And though it may seem confusing at first, thinking about weight quickly becomes as natural as knowing the hook size.
I use centigrams because it’s easiest for me, but some anglers think in grains instead. Ounces are not a good choice for fly fishing weights, because the increments aren’t small enough. (I don’t know anyone who wants to split fractions and think in 64ths out there.)
Some anglers choose to tie their #16 nymphs in multiple different weights, with various bead sizes. But my approach is simpler. Most of the #16 beadheads in my fly box are about 12-15 centigrams, so I round up and think of my #16’s as 15 cg. My #14’s are 25 cg, and so on. This system works well for me, because the bigger flies in my box are also heavier. It’s a simple approach that I’ve come to after trying other systems.
I can fine tune the weights because I use lead wraps behind the bead head, usually to about mid-shank. Here is my chart for nymphs:
Understand that the chart above is based on the hooks I use and the way I tie flies. The weight of your own flies may be quite different. There are some exceptions in my fly box, as well. For example, I tie my stoneflies and Polish Woven nymphs about 10 cg heavier than the chart above.
Additionally, here’s are the weights of the split shot that I use:
#1 30 cg
#4 20 cg
#6 10 cg
An advanced angler knows the weight required to get an excellent presentation in the target zone. My own understanding started by buying an inexpensive gram scale. But it took a while before I could look at a piece of water and think, “I need fifty centigrams here.”
This is the affordable AMS-100 gram scale I’ve used for ten years or more.
So, if I’m fishing a #12 stonefly, and I’m getting great drifts with no action, then I may want to try smaller flies. And I know I can change to a pair of #14’s but still have the same sink rate. Likewise, while fishing two #16’s in a gliding flat, I may swap out to a single #14 as I move into pocket water, but I’ll still maintain (nearly) the same weight. Alternatively, I may clip the #16 from the tag and add a #6 shot five inches up from the point fly.
This is the direct advantage of knowing your weights. Fly changes become more deliberate and less experimental. Efficiency improves, as does your confidence to read water and the ability to fish it well.
But knowing the weight at the end of the line is also a great advantage when considering the rest of the rig in your hands.
Weights and the Other Stuff
On my standard Mono Rig with an upstream tuck cast, I can fish 25 centigrams at 25 feet with negligible leader sag. But fishing beyond that distance requires either more weight, a thinner leader or a suspension tactic.
Knowing these stats makes fishing easier for me. I’ve tested weights, distances and leaders enough that I have confidence in the conclusions. I know what is possible at 25 feet, and I know how to adapt to get a good drift at 30 feet.
It’s all interactive. Choosing five feet of 6X instead of four feet of 5X requires less weight in the flies to get down. And the material resistance of a large, leggy stonefly helps hold the fly in the strike zone once it’s there. The stone counteracts the sag of a thicker butt section in my euro nymphing or tight line setup, while that thicker leader also provides more turnover power at distance. The best anglers understand that there are many different ways to accomplish the same thing.
Knowing your weights and measures is about understanding how to balance the elements of your fishing rig. It’s a give and take. But it’s up to you to first know what is being balanced. It’s the design of the leader, the weight of the flies, material resistance and distance. Put numbers to these things, and know your stats.
Then, begin to form an understanding of how to adapt these elements to achieve the necessary balance and change the outcome — to cast a tight line further with less sag or to cast a dry line closer with more s-curves.
Think of the principles covered in this Troutbitten short series as basic knowledge, as theory for understanding more about the way each element in your rig compliments the others. Then get out there and ask some questions of yourself. Learn a little each time, until you eventually piece together a system of weights and measures. And have fun out there.
Fish hard, friends.
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Enjoy the day.
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