Understanding Hydrodynamics and Superfine Nymphing

More and more I am seeing anglers leaning towards nymphing with superfine leaders, tippets, flies, and rods. The availability of European nymphing rods on the market is driving this superfine nymphing trend and I suspect popular opinion will move closer and closer to a 10+ foot 1 or 2 weight configuration for this style of fishing. There's a few things about superfine nymphing that probably could use explaining. For example, to most fishermen it seems extremely foreign, or unnecessary to be fishing a 7x tippet while nymphing with a 2 weight rod. In the next few paragraphs I’ll aim to shed some light on the “why?” behind this technique. 

The theory behind fishing superfine tippets is based on the fact that a fly sinks faster when it’s attached to a thinner diameter line. A downsize in tippet from 4x to 6x sinks the same fly pattern twice as fast because there is less resistance from the line hanging the fly in the water column as it tries to sink. A further drop to 7x tippet and the fly will drop like a stone. TroutHunter 4x tippet comes in at a diameter of .007” while 7x comes in at .004”. When talking about tippet size it is more important to understand diameters than simply the “x” size you are fishing. Downsizing tippet diameter can help today’s angler tremendously because it lets you sink small flies into a zone more quickly. When wild trout see a lot of fishing pressure in clear running rivers, they quickly adapt to eating smaller food items they deem as safe. 

Drag is another factor that is not only highly responsive to the diameter of the anglers tippet, but also the build of the leader. Minimal resistance is created in the water with a finer diameter tippet which means your fly will fish more true to the drift. This means better contact with the fly, getting in the strike zone quicker, and more sensitive registration of strikes. I like to downsize tippet when fishing deeper water especially in clear rivers where fish can see further and are more apt to eat smaller flies. There is a balance I like to achieve between the depth and speed of the water I’m fishing, the weight of the fly, the hydrodynamics (build) of the fly, and the diameter of the tippet. For water 2-4ft deep, I like a bead size in the range of 2.5-3.5mm depending on the water speed, slower water, lighter fly. The leader also plays a big role in this technique. It’s common to see 6-8lb butt sections used for lengths of over 25ft. A fine butt section on your nymphing leader means less mass hanging out of the rod tip and therefore less drag on the fly at any distance when compared to a 12-20lb butt section. The sensitivity is also much higher with a fine long leader because of increased connection to the fly. Less drag and sag created between the rod tip and water allows the angler can detect bites quicker and track drifts more truly through tight zones.

With a lesson in hydrodynamics and tippet resistance on a sinking fly, the angler will quickly understand there is an endless combination of fly types, bead sizes, and tippet sizes you can use to imitate different food. The question now is what rod will do it all? Most nymph rods on the market today are widely versatile. If you are more geared towards always fishing fine tippet, the 1002 and 1093 T&T Contact Nymph Rods protect 7x tippet and sling small nymphs at distances with ease. Diamondback Fly Rods are set to release a competitive alternative to these rods with the “Ideal Nymph Rod” this spring. The right rod matters because if a blank is too stiff or unevenly balanced it will break off light tippet on hooksets. It can also make casting long light leaders and flies more difficult, and will generally inhibit the sensitivity of the rig that makes this technique worthwhile. 

The fly design is also crucial for perfecting the superfine nymphing technique. My favorite way to use this is in clear rivers where more fish shy away from eating bigger food items. The Spanish have popularized the Perdigon nymph, a bullet shaped epoxy body fly designed to imitate mayfly nymphs found in cold fast flowing rivers. This fly is very hydrodynamic, meaning it sinks like a stone when thrown in the water because it has minimal resistance due to the lack of materials protruding from the body of the fly. A size 12 perdigon will reach the zone in a big swirl of water much faster than a heavy stonefly pattern because it has such little resistance in the water, compared to the stonefly with large appendages and dubbing. Fewer fibers and added materials creates less drag on the fly in the drift and allows it to sink faster. This gives the angler more control over the drift and allows you to be sure of where the fly actually is in the water. 

One crucial element to this style of fishing is leader construction. In my mind, there is no golden leader that will do everything for you. Leader design is always evolving to the angler's needs and conditions throughout the year. There are a lot of combinations to deliver a fly for fish, but some leader designs can outshine others on any given day. Each angler develops a unique style of fishing over the years, and something that might work for me might not work for you. Leader construction is all about fine-tuning the leader into something that you are comfortable fishing with and have the utmost confidence in.

Looking at the material side of things, Maxima Chameleon has been used for years in the competitive scene and is considered one of the best materials to construct leaders from for a variety of reasons. With low visibility, great energy transfer, and a ton of different sizes it's a clear winner for versatility.  When Cam and I met at a youth team clinic years ago it was normal for people to fish 25lb,20lb,15lb butt sections in many nymphing scenarios. Today I would consider this to be extremely thick and the euro nymphing scene has gone to the lighter side of things over the course of 5 plus years.

Looking at how a lighter leader affects the path of flies in the water is crucial to understanding why this method is getting more and more popular. With a lighter leader not only do you have less drag but it also increases sensitivity of the drift which leads to more fish in the net. A lot of euro nymphing leaders aren't capable of fishing thin tippet, but combined with the right rod it can allow anglers to fish 6.5x,7x, and 8x very effectively without putting unwanted stress in the tippet. This can be great when fishing pressured fisheries or places that tend to have spooky fish. In conjunction with this, thin euro leaders are able to turn over smaller flies with ease compared to a larger leader which can drag smaller flies through the water.

Primarily to start with an ultra-fine leader the material has to be thin, but stiff enough to maintain accuracy. The last thing you want is a limp leader that conveys no power from rod to flies. Opting a longer sighter in my opinion helps maintain more control over the drift and allows the angler to fish further away in hard to reach pockets or riffles. My current leader formula is

  • 10ft of 6lb maxima chamelon

  • 6ft of 5.5lb French Camou

  • 4 ft of 4x Cortland Tri-color Indicator Mono

    Tippet diameter and leader construction, combined with hydrodynamic fly design, and the right rod to fish it. Awareness of these details will help the angler understand and master the dynamics of superfine nymphing. Next time you’re out and around you suspect the fish are getting on small bugs, see how small of a fly you can sink into the zone with 7x tippet, you might just surprise yourself and the fish! 

jack arnot