It is known by different names depending on the author, Bucket Cast or Hump Mend being the most popular ones. I first read about this technique close to twenty years ago now. At the time I was far from possesing the skills needed, as proved my clumsy first attempts. I used to comfort myself by thinking that its use in practical situations was very limited; but that was just a cheap excuse to avoid some frustrating training sessions.
It isn’t that unusual to find a fish feeding in the slack water upstream of a submerged rock, or in the pocket water behind it, is it? There, a conventional straight line cast leaves the fly line at the mercy of the fastest currents downstream of the fish that will make your fly to drag immediately.
—OK, you can use a Puddle Cast —you say.
The problem is that, by its very nature, a Puddle Cast asks for an upwards forward trajectory, resulting in the line closest to the rod tip landing first on the fastest current, which consumes the moderate amount of available slack before the fly touches the water. Drag again. At once.
Another common situation is that of a fish patrolling super slow water, parallel and beyond a very fast current tongue. Of course, a straight line cast is completely useless. Even an exagerated Reach Mend upstream will result in our fly dragging too soon. I found —again— this scenario this past season; a situation involving nerves, frustration, some swearing and a big brown trout —that, miraculously, did bear a whole series of my failed attempts, eventually taking my dry fly.
That day I really regretted having left aside the Hump Mend from my training sessions for so long, as it was the obvious solution to that problem.
What the Hump Mend provides is a considerable amount of slack line, concentrated in a pretty small area of water. If you manage to place that pile of line between your fly and the problematic current —i.e. beyond the fast water, to give it some line to “eat” before tension reaches the fly— get ready to enjoy a long drag-free drift.
In my view, understanding how a cast works helps a lot in learning the skill. In this regard a Hump Mend is just a vertical transverse wave traveling down the line. It is similar to a Curve Mend, although in the latter case the wave is made in a horizontal plane. Start practicing the Curve and that will lay the foundations for the Hump.
- Set up two targets: one representing the area where the fly should land, the other one being a line on the ground representing the outer limit of the fast current you’d have to overcome. The pile of slack has to land beyond the “current”, while the fly lands on target.
- Although some authors recommend to practice placing the pile of line at different distances from the rod tip —in order to address currents from close to far—, I find that approach more oriented to casting demos than to practical situations. If you train yourself to put that slack line at the line tip at all times, you can counteract any conflicting currents between you and the pile. The advantage is that it is easier to get proficient when you don’t need to constantly think of the timing of the mend itself to place the slack at different distances.
- For the transverse wave to reach the line tip you need a very crisp stop on your forward cast; any soft deceleration at the end of the stroke will result in a shorter travel for the transverse wave, and it will fail in reaching the other end.