The Hunt For Big Fish with Larry Dahlberg

Do they roll big bunker flys over beter, or are they no big deal?

The subject of leaders is one of the least understood topics in all of fly fishing. Contrary to popular opinion, it is impossible for a tapered leader of any kind to "kick" a fly over. That is, unless you tie the leader "backwards" with the heaviest sections forward!
The momentum of the line is what carries and overcomes the wind resistance of the fly. The line must achieve enough velocity to propel the fly at a high enough rate of speed that its' own wind resistance is overcome enough to allow its' own momentum to carry it far enough that it pulls the leader with it.
Having a leader with a butt section that is as close to the same stiffness and diameter of fly line itself is a good place to start as it eliminates the possibility of a hinge at that point.
Obviously a shorter leader will be easier to turn over with a large fly than would a longer one.
The answer to solving the problem of casting larger flies is three fold:
1) Most importantly the caster must throw a tight, high speed loop and have near perfect timing.
2) The line itself must be heavy enough to overcome the natural wind resistance of the fly. (the "head" of a 10 weight line weighs about 300 grains)
Take a 300 grain hunk of lead and glue it to the nose of the fly, then just toss the fly like you would a baseball. If the 300 grains won't carry the fly it's unlikely anyone, including King Kong with a 12 weight would be able to cast it very far or with any pleasure in the process.)
3) Design or choose flies that have the least possible wind resistance but the largest appearance of size in the water. (That's why I invented Big Fly Fiber to compliment Flashabou on oversized flies)
Hope this helps!
best,
L

Understanding what you said,then why arn't fly lines tapered backwards? The truth of the matter is that the physics of fly casting is exactly as that of a bull whip. If the tapered leader holds true to the extended diameter of the line you will get the desired result simlar to that as a cracking of a whip.Obviously,the fly will offer resistance,but a stif twisted leader will do its best to resist and roll the fly over.

Sorry, but I have to respectfully tell you that you are laboring under a false assumption. The physicist and advanced fiber composite guy who brought graphite technology from england to the usa back in the sixties helped me research this same question when I was in my late teens. The explanation I gave you is the one he and I figured out.
Quick fly line history.
First lines were level lines. No taper. If you were a really good, high speed caster, they kicked horribly when they turned over due to the amount of energy generated when they change direction. In order to mitigate this, the mass at the end was reduced, or tapered. Most manufacturers tapered both ends and thus the double tapered line came into being. It made them slow down. It also made a line that was better for roll casting.
But, because these lines stayed "fat" beyond the 30 feet of "head" needed for creating enough weight to load the rod the line was designated for, they did not shoot very well. They simply generated too much friction. (It's the friction in the line that makes the loop turn over--it turns over because the lower section of the loop is traveling slower than the top part. In fact, if you had zero friction on the line as it passes through the guides, and there was no gravitational effect on the line being shot, the loop would never turn over!)(unless of course you stopped the line with your hand)
Fly line makers began making weight forward lines to reduce friction on the running line.
If you want to prove the taper thing to your self, just take a tapered fly leader in your hand and try to cast it with out a rod. Now turn it around and do it backwards. You will see what I mean.
Actually, if you discount the short forward taper, which is included for reasons explained above, weight forward lines are tapered backward! The bug tapers, etc are designed with a shorter forward taper based on the exact same principles.
best,
L

Thanks Larry for that explanation. I have not got into this argument in years, but if I do, may I refer them to your explanation.

As an Engineer, who works to fish (ask my wife about that one - LOL), many of our ideas about fishing tackle are incorrect. It is good to see that you set this straight.

Note; they call fly fishing an art, not a science. Perhaps it is.