Fly Casting Without Slack

Fine tune your cast and say goodbye to slack

Slack line may very well be responsible for more poor casts than all other faults combined. Think about it in terms of fishing with a conventional outfit. You would never lay a plug on the deck of a boat with six feet of slack line between the tip of your spinning rod and the lure and then attempt to make a normal overhead cast. Obviously, you would eliminate the slack by reeling in a bit. Fly-casters should follow suit. You simply cannot load a rod until the weight used to load it offers resistance to the tip.

You load all rods by moving the butt and relying on the line or the weight of the lure or bait to impart movement to the tip, and that can’t happen until all slack has been eliminated. Not only does slack affect how deeply the rod loads, but it impacts the speed, direction, length and effort of your stroke. Slack comes in many forms, and it’s either there before you begin your stroke or is introduced during the actual cast.

Before the Cast
Even though books and videos advise it, holding the rod tip well above the water at 10 o’clock or some other predetermined point before you begin your backcast doesn’t make sense. To understand this, observe Figure A. Look at the belly in the line of the rod at the 10 o’clock position. The caster will have to move the rod tip back several feet before the rod starts to load just before reaching the 12 o’clock position. Before picking your line off the water to make a cast, make sure the line is straight, or at least as straight as conditions allow. When your line is straight, you are putting tension on the rod tip even before you cast.

  • Here are three common tactics to straighten your line before making a cast.
  • Make a quick roll cast before you start your cast.
  • Use any current to your advantage by letting it straighten the line in front of you.
  • Make a preliminary short cast before picking up your line to make your actual cast.

During the Cast
It’s pretty easy to determine whether slack is entering the equation during the cast. Simply look at the loop as soon as your rod hand stops and the line unrolls. If it looks like any of the examples in Figure B, you have slack issues. Each of these three loops – there are others – represents slack and leaves two options, neither desirable.

If you start the forward cast with slack in your line, you immediately begin to waste energy because you are forced to pull this slack out. While the time lost to wasted energy is only a fraction of a second, it’s a critical fraction of a second because the rod will not start to load until the line comes taut. This is problematic. When you start your cast with slack in the line, the length of your usable stroke is shortened. In addition, you are forced to continue the forward stroke farther and more downward at the end of the forward cast, which can cause you to cast harder or rush the stroke subconsciously, generating shock waves in the forward cast and more than likely creating a tailing loop. The only other option is to wait until the line straightens completely. While this may sound like a logical remedy,believe it or not, it’s equally inefficient.

The solution to the problem is to convert your backcast into a smoothly unrolling loop. To do that, you must first understand the aspects of your stroke that caused your poor backcast.


Take a look at all three of the backcasts shown in Figure B. Each backcast represents a different issue, but all will result in shock waves on the forward cast because of slack.

You’ll encounter a similar problem, though usually less severe, if you wait for the line to straighten. It’s poor technique to allow the line to unroll completely before starting your forward cast. Casting instructors have advocated this for generations, but that doesn’t make it right. As long as the line is unrolling to the rear, it is putting pressure on the tip. If you move the butt forward just before the line finishes straightening, when the loop resembles a candy cane, the counterforce gives you an instant load. On the other hand, once the line straightens, the tip relaxes and the line starts to sag and fall, causing the caster to lose vital pressure on the rod tip.

When casters do let the line fully extend on the backcast, tension on the rod tip is lost for a split second. The slack that develops during this ever so short time frame often results in casts that are less than perfect. Remember, your main goal when casting should always be to unroll the fly uniformly and smoothly on both the forward cast and the backcast.


Slack Solution
No matter what, always resist the temptation to throw harder to overcome poor technique. This is a natural tendency, and many casters are guilty. Instead, remedy the problem. When you realize that you are muscling your cast — stop. Take a second and simply slow everything down.

Most fly-anglers have no idea how effortlessly they could cast if it weren’t for slack at different points. Your aim should always be to see how little, not how much, effort you can use on any given cast. In the case we’re discussing here, that means getting rid of and not creating slack line. It all starts with observing any slack in the line before you start the backcast, as well as any that you create during your backcast or forward cast.

Illustrations by John Digsby


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