Fly Casting- How straight is Straight Line Path ?

Making Adjustments on the Fly B.Gammel

a very astute casting student asked me recently, “I think I’m having difficulties keeping a Straight Line Path throughout the stroke. I must be doing something wrong ?”

i love these kind of comments. it shows the person is curious, really pays attention to what they’re doing and shows they’ve studied well. at this point i should say that his loops where ideal, nice and smooth, very close to parallel very nice loops, as nice as what we see Andreas Fismen performing in the 500fps slomo gif below. so, what was the problem then ?
since his casting was spot-on it obviously wasn’t anything he was doing wrong (loops don’t lie. they can’t) but simply his understanding of how rod tip travel should be for a textbook straight line cast but who could blame him ?
diagrams, books, videos and even in real, most instructors explain that just as in the diagram above, SLP (Straight Line Path) is a constant from one end of the stroke to the other. even in Jay and Bill Gammel’s awesome reference construct The Five Essentials of Fly Casting, this straight all-the-way-through concept is very easy to accept and take for granted.

“3. In order to form the most efficient, least air resistant loops, and to direct the energy of a fly cast toward a specific target, the caster must move the rod tip in a straight line.”

but is that what really happens ? lets take a closer look.

'SLP' Borger:Lovoll FC

first published in 2010, these findings aren’t anything new to some of us casting geeks but might be a sorta eye-opener for the non geeks, shedding some light for those who have asked themselves the same question as my student. just as we’ll see in the still below, in this study cast SLP is roughly a little bit more than a third of the overall stroke, most of the rod tip’s path has a mostly domed/convex shape with a somewhat flattened top. *
SLP length Borger:Lovoll

i won’t risk any absolutes but as far as i can tell, the only time we’re going to see a true, all-the-way-through SLP and its resultant tight loop will be when a non-flexible rod (the proverbial broomstick) is used to perform the cast. but even if the broomstick is somewhat frequently brought up in casting-geek circles and is a wonderful tool to understand a lot of casting concepts, it’s not something we use.
our ‘real’ rods bend, react to the forces we apply to them, get shorter as they bend and go back to their original length as they unbend and there’s the caster’s biomechanics and probably a billion other factors that are involved when considering rod tip path and even if they all where within my understanding, they’re not about today’s subject.

to conclude, after having shown this video and image to my student (ah, the beauty of bringing an iPad to lessons!) with a few explanations and demonstrations, you’ll most probably have already guessed it but here was the furthered response to his query.

– knowing this isn’t going to change your life, its just one of those ‘what we thought we where doing isn’t necessarily what was going on’ things.
– does this not-as-straight-as-we-thought SLP change anything in the way we should cast ? nope.
– provided you get the loop shapes you’re wanting to create, should you be doing anything differently ? absolutely not !
– if you want a straight line cast, keep on imagining your complete casting stroke is a straight one (and do all the other elements correctly) and you’ll get that tight loop and a straight line layout.

which in a certain manner, makes it resemble Saint Exupery’s elephant inside a boa drawing a lot more than your everyday ruler. at least in my eyes…

top image from Bill Gammel’s brilliant Making adjustments on the fly
regiffed video and adjoining image via Grunde Løvoll. click HERE for more of Grunde’s slomo studies on Jason Borger’s site: Fish, Flies & Water
elephant/boa drawing from Antoine de Saint-Exupéry: Le Petit Prince

note- although the loop shape in the gif is textbook ideal, Andreas’ casting stroke seems to be quite long considering he’s only false casting 10m (32.8ft) of line. my guess is he was casting at a fast rate which necessitates a wider casting stroke, perhaps something to do with getting a good visual result with the 500 frames per second camera.

39 thoughts on “Fly Casting- How straight is Straight Line Path ?

  1. Interesting article. I have often wondered how straight the actual travel of the rod tip is, particularly when the bend of the rod increases (and its associated return of the tip after flexing). It also raises the question of the “path of the fly”, in relation to the tip of the rod. I believe that a lot of casters slightly angle the rod to avoid the fly travelling directly straight over the tip (particularly on the back cast) and therefore the tracking (as Paul Arden of Sexyloops puts it – “The Birds Eye View) of the rod is tilted (maybe only a few degrees) to avoid the fly hitting the tip of the rod. I have experimented with bringing the fly directly back over the tip, but for me personally to achieve this, without hitting the tip of the rod, I have to slightly open the casting arc to avoid the fly hitting the tip.

    This subject becomes more interesting as you angle the rod from the vertical to the 90 degree horizontal (I believe the horizontal cast is one of the most useful in flycasting, particularly in the salt). Whilst I can get the fly to travel directly over the tip in the vertical and what I would term the true horizontal, I find it virtually impossible between the vertical and true horizontal to get the fly to travel directly over the rod tip. However, I believe that by getting the fly to travel directly over the rod tip we are achieving optimum use of energy of the flyline and rod (Trust this statement makes some sort of sense) 🙂

    I would be interested to know what other flyfisherman, and casters, believe is the true path of the fly, as they cast, in relation to the rod tip, particularly on the back cast, as I believe it’s relatively easy to bring the fly directly back over the rod tip on the forward cast.

    • hey Rob, thanks for your comment.
      here’s why there’s rod clipping of the line/fly in pure one-plane casts: in the case of a vertical cast the caster isn’t lifting the elbow/rotating the shoulder.
      Jason Borger refers to this as ‘Pistoning’ in his Foundation Casting Stroke chapter in Nature of Fly Casting. (photo below – Jason, i hope you won’t mind!)
      to get the same ‘over the rod tip’ on a side cast (regardless of casting angle) the elbow needs to go out then in, replicating the same up & down but in a different plane.
      what the lifting of the elbow does is ‘lift’ the line over the rod tip and everything’s all nice and straight and safe and pretty and all in one plane. give it a try.
      JB 'Pistoning' FCS

  2. “I would be interested to know what other flyfisherman, and casters, believe is the true path of the fly, as they cast, in relation to the rod tip…”

    That’s is a very interesting point of view and one that is normally neglected. In order to get a better idea of what really happens it helps to get rid of the old concept “line follows rod tip”, just because that isn’t true:

    Understanding that the line doesn’t necessarily follow the rod tip sheds new light on, for instance, why bad tracking is so detrimental to accuracy, and how an oval cast helps in casting heavy flies safely.

  3. hi Aitor, thanks for your input.
    Rob, “how an oval cast helps in casting heavy flies safely” reminds me that my ‘elbow-lifting over the rod tip’ suggestion is for the smaller, non-weighted say, dry flies or nymphs.
    although i’ll still ‘Piston’ for just about every cast i would never recommend one-plane casting for bigger, heavier flies such as streamers or teams of heavy nymphs. too many big ouch possibilities… 😆

    • I wasn’t thinking of the different planes between back and forward casts when mentioning the oval. Since the actual trajectory of the line depends not only on the tip path but on the angle between rod tip and line as well, an oval cast works in keeping a safe distance between fly and rod even if back and forward cast were in the same plane.

      Some stuff for a new post 😉

  4. sorry buddy but i’ve read that 16 times and i still don’t understand… 😆
    please explain differently how an oval cast can be done while casting in the same plane !

    • No, obviously it can’t be done in the same plane. But if the oval works in keeping us safe from big flies isn’t due to that difference in planes but in the position of the line in relation to the rod tip at the start of the forward cast. The line points upwards so to speak so when we accelerate it tends to go not only forward but upwards also.

  5. ok, ok. that’s better ! 😀 yup, the upwards sweep of the line tip as we reposition the rod tip from BC to FC.
    come to think of it, it’s doing the same thing as the rod tip… 😉

  6. Thanks Mark. For a newb caster like me, I always hear and read that concept of SLP, but had trouble following and picking it out in casting videos, making me feel like I wasn’t quite sure what I was doing. Although I still frequently don’t, at least I have a better picture in my mind. Additionally, thanks for bringing back memories of Le Petit Prince, gonna have to go get a copy and reread it.

    • hi Peter, sorry i missed your comment.
      glad this could be of help and thanks for your comment and enjoy the re-read !
      i read it again from time to time, every few years or so. its a good ‘refresher’ most adults could benefit from…

  7. Marc,

    I have been meaning to get back to this topic and finally got around to doing so. With your description, and thank heavens, the picture from Borger’s “Nature of Flycasting” (My learning style is visual, I admit I have trouble understanding written descriptions of flycasting techniques). I believe that if the line can travel straight over the rod tip then the energy of the flyline is being optimised, as opposed to any path that deviates, even slightly, from the SLP. Does this make sense?

    Having said that the “pistoning action” sounds interesting as a solution to over the tip casting. You outlined “what the lifting of the elbow does is ‘lift’ the line over the rod tip and everything’s all nice and straight and safe and pretty and all in one plane”. Okay, that sounds good, but although it is alluded to you in your comments it strikes me that the lowering of the elbow after the initial elbow lift is equally as important in this piston action, the “elbow up” position may start the rising of the fly over the tip, but it is the lowering of the tip that is essential in completing and achieving the final result.

    Do you know of any videos that demonstrate this technique. It’s my “visual learning” thing 🙂

    p.s. Still casting at the Fronton in Mexico City and the rainy season turns it into a shallow lake at times. Very realistic!

    Best regards,

    Rob Mellors

  8. hi Rob, glad you’re back !
    “I believe that if the line can travel straight over the rod tip then the energy of the flyline is being optimised, as opposed to any path that deviates, even slightly, from the SLP. Does this make sense?”
    very much so ! however, the very slight loss of potential energy when going out of plane is almost always negligible for most casting/fishing needs.
    i can think of two examples where straight/one plane casting will be crucial: competition-style distance casts (very few people do this so its almost irreverent… 😆 ) and extreme accuracy in either accuracy comps or for placing a light fly very accurately in front of a fish or in a very specific feeding lane etc, etc.

    now for a personal note: whether we do comps or not or have to place our flies in the proverbial teacup and even if we don’t regularly use it, in my opinion, if someone wants to be a really good caster they should learn to cast over the rod tip. as we see from Jason’s drawing it necessitates the use of all the arm joints and muscles and we’ll use the bigger/strong groups (the shoulder) to do most of the ‘hard’ work, the semi-strong elbow to do most of the rod rotation and then the weaker wrist and fingers to refine movement.
    people who rely on their elbow and wrist/fingers have to put all the casting force in those smaller/weaker groups and its more difficult to combine force and delicacy at the same time with the same joint/muscle groups. in other words, they’re missing out on a lot of potential they already have and this obviously hinders progression.

    “but although it is alluded to you in your comments it strikes me that the lowering of the elbow after the initial elbow lift is equally as important”
    of course ! what goes up has to come down ! 😆
    (it also says it in Jason’s drawing “lifting and dropping” and the little arrows point both up and down)
    so, in practical terms, the elbow goes up on the BC, stays there while the line is unrolling and then drops back to its initial position during the FC.
    just as the lift ‘lifts’ the fly line over the tip on the BC, the ‘drop’ on the FC not only facilitates a straight line path because we tend to drop thing straight instead of in curves but this also places the rod tip below line path at the end of the stroke preventing the line from hitting the rod tip.
    think of the whole movement thing as a mirror. i goes one way in one direction and when it changes direction it’s inverted. i hope that makes sense !

    as for videos, i’ll look around and post them if i find something that explains this well.
    (i’m getting ready for a 3 week fishing trip to the UK so it might be a while… 😉

    hope you’re having fun, take care.

    • Got it!

      Thanks for that Marc. Interesting how close the elbow is to the body at the start of the cast and how quickly it’s returned to that same position in the downward motion. Trust you had a good and successful trip to the UK.



  9. glad that helped, Rob !
    i really think your last comment should go over to that article, would you please copy and paste it and post it over there ? i’ll answer it there as its very relevant to the post. thanks !

  10. Hi Marc
    Please correct me if I am wrong
    If the drift very important to create a SLP?
    Best regards

      • Hi Marc,
        I red the paper and they are very interesting.
        What I can say is that I recently discovered the drift and the consequences on fly cast.
        Now I can cast heavy flies or bulky flies without fear to hit the rod. Finally I think that saltwater fisher promote lateral cast, oval cast in order to avoid heavy flies, but I think there’s a certain abuse of this non vertical cast. What do you think?. Best regards Dario

        • glad to see you’re finding what’s working for you, Dario.

          abuse ? not at all, whether it’s with big flies or small, at short, medium and long distances, some sort of Elliptyc cast is the norm for the vast majority of fly fishers around the world.
          if anything it’s normal, whereas pure vertical casting (where the the complete loop, top and bottom fly line legs are in the exact same plane as the rod) isn’t seen very often apart from the exception of target competitions and IFFF testing.

          thing is, most casting diagrams and explanations show or talk about ‘one plane’ casting but few people can actually do it.
          they’re showing or talking about something they think is happening instead of actually observing what is happening…

          • Hi, Marc,
            For me, my ideal model of fly cast is that of Philip Pilot; in a video that you have probably seen, he cast both vertical and lateral cast with the same muscle. He use double haul and (what I like very much) he does not move the body back and forward. That means that he use the right muscles with minimum effort.
            Probably in the future I will change my opinion but at the moment, for me the Philip Pilot casting technique is the best.
            My compliment for the website, it is wonderful.
            The slow motion of the vertical cast was very important for my comprehension; is actually the rod the go down respect to the fly line during the drift?😊
            Best Regards

    • well, you could always start with what’s at the top of this page, Rob…

      i wouldn’t call Flip’s loops trailing loops. in fact i don’t use that term at all because it doesn’t really mean anything even though its somewhat widely used.
      more on the subject here

      anyhow, even if its narrowish, he’s just using an Ellyptic cast, so, what you’re calling trailing lops isn’t a fault at all, it’s just normal, specially considering the camera’s perspective. they’re ‘crossed loops’.

      • Trailing loop is a term that is widely used and presumably it means something to somebody, In an explanation given to me by a FFF casting instructor you’re right in saying that it is not perceived as a fault and is actually seen as a fairly effective form of casting. That’s one of the interesting things about the world of flycasting, it’s different viewpoints! 🙂

        • “Trailing loop is a term that is widely used and presumably it means something to somebody”
          cant disagree there but it’s also generally used to describe a ‘fault’. this happens when groups such as the IFFF tend to think that only pure verticle/all-in-one-plane casts are good and normal.
          said group (as a whole and specifically the exam commitee, not specific members) tends to forget that defining something such as a trailing loop needs to be done in the very specific context of that particular portion of the cast while taking the perspective of the viewer into account.
          the term ‘trailing loop’ with its usual ‘negative’ connotation completely disregards other types of casts that are even part of the IFFF exam curriculum: the Roll cast for the CCI exam and the subsequent Spey casts in the MCCI. its is absolutely impossible to perform these casts without a crossed loop.

          definitions need to apply to all casts or otherwise they don’t mean anything and just prove things haven’t been thought out well enough. the IFFF has been working on definitions now for something like ten years and they’re still incoherent. among others, this is one of the reasons i decided years ago to no longer be a part of that group.

  11. anyhow, this continued thread has reminded me of how uninterested i am in fly casting at the moment and the somewhat bitterness and unclear thinking of my recent responses show that, i guess so, sorry, i shouldn’t have even responded.
    it’s a passing moment, maybe.

Comments are closed.