I have rescued those clips provided below shot years ago, when I was studying in depth the mechanics of Spey casting, reading all the material I could find (printed and on-line), watching loads of how-to DVDs and videos from the internet, and analyzing my own casting and that of my students by means of slow motion video.
Their publication at that time prompted quite a few dismissing comments on fly casting forums, and I eventually removed the videos from the public view.
After a recent conversation with a fellow casting instructor who showed real interest in that material and wanted to use it, I decided to upload it again together with some brief comments.
It was Alejandro Viñuales —my fly casting mentor— who pointed me out to the fact that no matter how skilled authors were with a rod in hand, most of the explanations about Spey casting mechanics were at odds with what basic Physics teaches us.
It looked like some ideas from the past —when our knowledge and the means to gain it were much more limited than nowadays— were being passed from one generation of anglers to the next without giving them a second thought, exclusively based on the principle of authority.
The very foundation of all that theoretical “building” relied in one of those misunderstood concepts: the “anchor” and its function.
The departure point was the idea that fly casting in general works by means of loading and unloading the rod; in overhead casting you wait for the line to unroll completely before starting the following stroke —failing to do that, being a fault—, but on Spey casting the line doesn’t fully unroll, leaving only about half of it to pull on with your rod. How to explain the efficiency of the Spey technique taking that into account? Keep it simple, they said: it was the anchor on a Spey cast what helped in loading the rod compensating for that shorter line length.
But simple and simplistic are totally diffent things.
In Physics terms, rod load is based on the action/reaction law. When the rod pulls on the line the latter reacts by pulling on the rod with a force of the same magnitude and opposite direction; as the rod is flexible, it gets bent due to that force.
The rod gets bent even without a line due to the inertia of its own mass, but we can leave that issue aside here. The main concept is that for the rod to get loaded it must pull on the line in order to ”activate” the action/reaction mechanism.
Forces aren’t good at turning corners.
Take a one meter long piece length of string and fold it in two on top of a table, shaping a “U”; then pull on one end, does the other end move? I bet it doesn’t. You could also tape one end to the table and pull on the other end —“anchoring” it—, but you won’t feel any resistance either. By pulling on the free end you don’t exert any force on the anchored end, and without a force acting on the anchor the latter can’t exert any reacting force on your fingers.
The only way of moving one end of the string by pulling on the other one is by using some sort of simple pulley, but obviously there is no pulley in a D-loop.
What the following videos show is another version of the scenario described above.
Look how while the casting stroke is performed, the line tip remains still on the floor. It is only after the stroke is finished that the very small tension reaching the fly leg manages to make the remaining short length of line slip backwards. Note also that at that instant when the line tip slides back the rod is already unbending, not getting bent.
So, the force that the caster applies to the line section in the rod leg of the D-loop is not felt at the tip of the line section forming the fly leg; even if you would tie the line tip to a ship’s anchor, the latter wouldn’t be affected by any force, and no action, no reaction.
In summary: the anchor of a Spey cast doesn’t load the rod; it can not do it!
Now a very simple exercise for you to check by yourself the validity of this analysis:
Rig a rod with line and leader. Form a D-loop laying on the ground. Hold the leader end lightly between two fingers of the line hand and make a roll cast. Do you feel a pull in your fingers during the casting stroke?