Odds 'n' Sods of Information and Opinion

Heavy tip and light fly vs. light tip and heavy fly

Light or Heavy Sinktip with a Fast or Slow Sink Fly?

I have been using Airflo FLO sinktips lately and they made me think about something I usually do instinctively and that is the process of matching fly, leader and sinktip to the fishing situation. In this case it was a matter of deciding on a heavy tip and light, slow sink fly vs. light tip and heavy, fast sink fly. For those not familiar with FLO tips, each one is 10’ long composing 2.5’ of intermediate followed by 7.5’ of T material. A set of four consists of tips made with T7, T10, T14 and T18. Such a setup gives us the choice of fishing a run with different tip and fly sink rates.

The basic difference is this: a fast sinking fly gets down on its own while a slow sinking fly needs to be dragged down by the sinktip. So lets see what this does for us.

  • A fast sinking fly lets us use long, skinny leaders giving us better separation between fly and sinktip, producing less chance of spooking fish. This combo also cuts through current very well.
  • A slow sinking fly needs a short leader otherwise it will hang high while the sinktip is low. The short leader places the sinktip and fly in close proximity, giving the fly a tethered look which will reduce its ability to move in current.

  • A light, slow sink fly will move easily in currents and look alive.
  • A heavy, fast sink fly will resist moving in current so it will not have a lively look.

Bottom Line
  • Heavy, fast sink fly on a short, stiff leader will look lifeless
  • A light, slow sink fly on a long leader will not get down
  • A short leader + slow sink fly or a long leader + fast sink fly is the best compromise

Now which to use? Well, that depends on the river conditions. Yesterday I was casting to the far bank which sloped off gradually. The run was wide so I had plenty of swing space. The fish holding area was off the bank a fair bit. If I used a fast sink fly there, I would lose flies continually as the fast sinking fly would hang up almost instantly along the shallow river bank. Since I don’t fish this creek often, I wasn’t familiar with the topography of the far bank and lost a few flies before I switched over.

On a different run, I had a narrow deep pool with a limited swing arc. I needed to punch the fly down fast so the fast fly, long leader setup was best. Had I used the slow sink fly combo, the fly would have been out of position over the entire swing.

So much of the decision is based on the need to either get down fast or get down slow. Keep in mind that a slick, weighted fly will get down faster than any sinktip so it will lead the way down. All the more reason to use longer leaders as we will not only speed the rate of descent, but we will gain greater depth. The longer leader gives us greater horizontal separation between tip and fish, and it will also give us greater vertical separation as well.

So part of our thinking has to be based on the notion of which part of our terminal rig will be responsible for gaining depth: sinktip or fly. We’re accustomed to thinking solely interns of the sinktip being the depth driver, but in reality a weighted, very fast sinking fly when used with a very long, skinny leader can actually achieve significant depths on its own. It’s just awful to cast which is why we don’t see too many people using this approach.

So in the end when fishing this creek, I moved between heavy tip and slow sinking, light fly to the reverse combo depending on current, the speed needed to get the fly down, and the size of the swing arc more than just the depth. There are so many ways to fish a fly at a specific depth, our thinking really should be about the other factors.

Having the FLO tips with me gave me a choice between using a heavily weighted fly and the T7 tip versus a light, higher drag, slower sinking fly and a T14 tip. Thinking in these terms, it’s about the fly, leader and the sinktip in partnership to get the right depth and presentation rather than just considering it as a ‘sinktip only’ problem.