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The Science of the Spey Casting

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Preface by VARIVAS Staff

Back in early 2023, not long after the world began recovering from the COVID pandemic, we received a message from San Francisco’s legendary Golden Gate Angling & Casting Club—one of the oldest continuously operating angling clubs in the nation, with a deep and storied history. They invited us to become a sponsor of their annual Jimmy Green World Championship of Spey Casting, better known as Spey-O-Rama.

At the time, VARIVAS was still a relatively unknown brand in the U.S. market despite our long-established reputation in Japan. What we didn’t realize was that many competitors had already been using our AIRS shooting lines and had known the VARIVAS name for years. Because of the competitive nature of the sport, however, VARIVAS line was something of an ‘inside secret’ that was rarely discussed openly.

VARIVAS America’s staff have encountered similar stories surrounding many of our products in the U.S.—dedicated and resourceful anglers importing gear directly from Japan and quietly sharing it within trusted circles, whether for competition casting or real-world fishing success.

To all of those longtime users and supporters who recognized the quality of our products before we officially arrived the USA:  THANK YOU!  We truly appreciate your trust in the VARIVAS name.

And to those who may have preferred keeping it a secret… we apologize, but the word is out. Today, anglers across the country can easily order from more than 100 different types of high-performance, highly specialized VARIVAS fishing products, all shipped directly from our U.S.-based warehouse in Oregon.

VARIVAS AIRS Shooting line —  is trusted by champions and relied upon by many of the world’s top Spey casting competitors.

— Check out the video above and accompanying article below —

Championship Spey caster and professional guide Travis Johnson
shares his experience and insights on the VARIVAS AIRS Shooting Line,
including how it performs in both world-class competition and real-world fishing situations.

The Science of the Spey Casting

How a World Champion Fly Fisherman Chooses His Running Line

Why the right running line can mean the difference between a good day on the water and a great one

There are anglers who fish, and then there are anglers who have dedicated their lives to understanding every nuance of the sport — the physics of the cast, the behavior of the line, the subtle interplay between equipment and environment. Travis Johnson belongs firmly in the latter category. A full-time fly fishing guide and outfitter working the legendary waters of the Deschutes, Sandy, and Clackamas rivers in the Pacific Northwest, Travis has spent countless hours pursuing winter steelhead with two-handed rods. He has also stood on the world stage as a four-time world casting champion who has broken the world record multiple times. When Travis talks about running line selection, the fly fishing community listens — and for good reason.

For many anglers, running line is an afterthought, a utilitarian component that simply connects the shooting head to the reel. But Travis’s philosophy challenges that assumption at every turn. In his view, running line is a critical performance variable, one that directly influences casting distance, line management, cold-weather fishability, and ultimately, success on the water. His preferred choice — VARIVAS running line — is not a casual endorsement but the product of years of competitive casting, professional guiding, and relentless refinement of technique. Understanding why Travis chooses VARIVAS, and more importantly, how he selects the right pound test for each application, offers a masterclass in the kind of detail-oriented thinking that separates elite anglers from the rest of the field.

Matching Pound Test to Purpose: A framework built on experience

One of the most practical and immediately applicable aspects of Travis’s approach to running line is his systematic framework for matching pound test to rod weight, grain weight, and fishing conditions. Rather than defaulting to a single line for all applications, he has developed a tiered system that accounts for the specific demands of each fishing scenario — a system refined through years of guiding clients across multiple river systems and competing at the highest levels of the sport.

At the lightest end of the spectrum sits the 24 lb VARIVAS AIRS Shooting line, which Travis reserves for light spey and switch rod applications. This includes trout spey setups and lighter switch rods where finesse and delicacy are paramount. As a general rule of thumb, he applies this pound test to grain weights under approximately 350 grains. The logic here is straightforward: lighter grain weights demand a running line that complements the subtle energy transfer of a lighter shooting head, and the 24 lb VARIVAS AIRS Shooting line delivers the sensitivity and shootability that these setups require without introducing unnecessary bulk or stiffness into the system.

Moving up the scale, the 30 lb VARIVAS AIRS Shooting line occupies what Travis considers the most versatile size in the lineup. This is the pound test he reaches for during competition casting, summer steelhead fishing, and general applications involving 6 wt, 7 wt, or 8 wt rods. For the majority of spey and switch rod anglers, the 30lb represents the sweet spot — versatile enough to handle a wide range of conditions, light enough to shoot with exceptional efficiency, and manageable enough for anglers of varying skill levels. It is, in many ways, the workhorse of the VARIVAS lineup, and Travis’s endorsement of it as the go-to choice for most fishing situations reflects both its performance characteristics and its accessibility.

The 36 lb VARIVAS AITRS Shooting line is ideal for rod grain weights above 500 or 600 grains.  Travis also finds the 36 lb particularly well-suited to spring and summer conditions. At heavier grain weights, the additional diameter of the 36 lb provides a more balanced relationship between the shooting head and the running line, ensuring that energy transfer remains efficient and that the line handles predictably through the guides. The seasonal dimension of Travis’s recommendation is equally interesting — during warmer months, when hands are more supple and grip is less of a concern, the slightly thicker 36 lb shooting line is easier to manage and control, particularly during the retrieve and when preparing for the next cast.

At the top of the range sits the 47 lb AIRS Shooting line, and this is where Travis’s winter steelhead expertise becomes most evident. The 47 lb is, by his description, approximately as thick as conventional fly line, which means it sacrifices some of the ultra-thin shootability of the lighter options. But what it gains in return is critical for cold-weather fishing: it is substantially easier to grip when fingers are cold, stiff, and unresponsive. Anyone who has stood knee-deep in a winter river, hands numbed by near-freezing water and air temperatures, understands the challenge of managing thin running line under those conditions. The 47 lb AIRS Shooting line addresses that challenge directly, offering the tactile security of a thicker line while still delivering the core performance benefits — floatability, low memory, and shootability — that define the VARIVAS AIRS product line.

The Performance Pillars: Why VARIVAS stands apart

Understanding which pound test line to use is only half of the equation. The other half is understanding why Travis has committed so thoroughly to VARIVAS as his running line of choice across all of these applications. His reasoning is multifaceted, grounded in both the technical demands of competitive casting and the practical realities of professional guiding, and it illuminates the specific properties that distinguish a truly high-performance running line from a merely adequate one.

The first and perhaps most immediately noticeable characteristic of VARIVAS running line is its exceptionally low memory. Memory — the tendency of a line to retain the coiled shape it held on the spool — is one of the most persistent frustrations in fly fishing, particularly with monofilament running lines. A high-memory line requires extensive stretching and warming before it will lay flat and shoot cleanly, and even then, it may revert to its coiled state during a long day on the water. Travis notes that VARIVAS AIRS Shooting line is so resistant to memory that it performs reliably even after sitting on a spool for years without use. This is not a trivial advantage. For a guide who may be switching between multiple rod setups throughout a day, or for a competitive caster who needs consistent performance from the first cast, a line that is ready to fish straight off the spool represents a meaningful practical benefit.

The second pillar of Travis’s endorsement is the line’s knot-tying characteristics. Monofilament running lines vary considerably in how well they accept and hold knots, and a line that slips or weakens at connection points is a liability in any fishing situation. VARIVAS AIRS Shooting/running line behaves predictably and reliably when knotted, making it accessible to anglers at all skill levels. Whether connecting the shooting/running line to a shooting head or securing it to the reel, the line responds to standard monofilament knot-tying techniques without requiring specialized knowledge or exotic connection methods. For Travis’s guiding clients — many of whom may be relatively new to spey fishing — this user-friendliness is a genuine asset.

Tactile quality is the third factor Travis highlights, and it connects directly to the broader theme of performance under real-world conditions.  VARIVAS running line has a suppleness in the fingers that makes it comfortable to handle during the retrieve, during line management between casts, and during the shooting phase of the cast itself. This suppleness is not merely a comfort consideration — it directly influences how cleanly the line feeds through the guides and how effectively an angler can control the line during the cast. A stiff, wiry running line creates friction, disrupts loop stability, and ultimately costs distance. A supple line moves through the guides with minimal resistance, contributing to the kind of clean, efficient energy transfer that produces maximum distance.

And distance, ultimately, is where Travis’s competitive credentials become most relevant. The reason he uses VARIVAS Shooting line in world championship competition — and the reason he has won those championships and broken world records — is that it shoots better than the alternatives. The combination of low memory, suppleness, and surface characteristics produces what Travis describes as optimal loop stability with minimal guide friction. In competitive casting, where every foot of distance matters, this performance edge is decisive. But the same principles apply on the river, where a longer, cleaner cast can mean the difference between reaching a spot or falling short.

The Floatability Factor: A deeper look at surface performance

Of all the performance characteristics Travis associates with VARIVAS AIRS Shooting/running line, floatability deserves particular attention because it operates on multiple levels simultaneously, influencing casting performance, line management, and the overall fishing experience in ways that are not always immediately obvious.

Floatability, in Travis’s framework, refers to the proportion of the running line that sits on top of the water’s surface rather than sinking below it. This might seem like a minor detail, but its implications cascade through every aspect of how the line performs. A shooting/running line that floats high on the surface experiences less water resistance during the shooting phase of the cast, which translates directly into greater distance. When the line is lying on top of the water rather than partially submerged, it lifts off the surface more cleanly at the initiation of the cast, reducing the energy required to overcome surface tension and water resistance. The result is a more efficient energy transfer from rod to line, and ultimately, a longer cast.

The second dimension of floatability is its contribution to loop stability. A line that floats consistently and maintains its position on the surface behaves more predictably during the cast, forming cleaner loops and tracking more reliably through the air. This predictability is particularly valuable in competitive casting, where consistency is as important as raw distance, but it also matters on the river, where a well-formed loop is essential for accurate presentation and effective line control.

The third and perhaps most practically significant aspect of floatability is its effect on tangle reduction. Shooting/Running line that sits on top of the water and remains relatively dry is far less prone to the frustrating tangles and knots that can plague a day of fishing. Wet, sinking running line tends to clump, twist, and tangle — particularly when it is being managed in coils during the retrieve or when it is lying on the water between casts. A line that floats and stays dry maintains its separation and organization, feeding cleanly through the guides on the next cast and requiring far less time and attention to manage. For a guide who is helping clients fish efficiently and enjoyably, this tangle resistance is not a luxury — it is a fundamental improvement that keeps the focus on fishing rather than line management.

A Question of Color: The Orange and Yellow debate

A frequently asked question that Travis gets is: Which color is better, the yellow or orange, AIRS Shooting line?  The answer, is simple: there is no performance difference between the two. The choice between orange and yellow is purely a matter of personal preference.  Travis’ personal preference is the high-vis orange color.

Conclusion: The wisdom of specificity

Travis Johnson’s appraoch to line selection reveals a philophy of specificity  — the conviction that informed equipment choices, made with a clear understanding of the conditions and demands involved, produces better outcomes.  His deep understanding of the performance properties that matter most, and accute attention to detail, reflect the mindset of someone who has spent years pushing the boundaries of what is possible with a spey rod in hand.

For anglers looking to elevate their spey and switch rod fishing, the lessons here extend well beyond the specific merits of any single product. They point toward a broader practice of intentional equipment selection — of asking not just what works, but what works best for this rod, this grain weight, this season, and these conditions. In a sport defined by its complexity and its rewards, that kind of specificity is not obsession. It is expertise.

VARIVAS Products used in this report:

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