Weighting nymphs for streams and rivers

[GGY]

Oh no - slagging match! Opening salvo's fired!

I should not have said flow rate...I should have said VOLUME. (Let's say compare the Vaal to the Zambezi...may be similar CUMECS per second but the Zambezi's VOLUME of flow past is much more. I dunno how else to explain it. The European rivers flow with more volume than ours...some of the anglers fish with inflatable life jackets in fact. Some of the other anglers have told me that some of those rivers are unreal in terms of strength. .

VOLUME = Unit is cubic metre (m^3).
CUMEC = CUbic MEtre per seCond (M^3.s^-1).
Defined as the VOLUME of water passing a cross-section of water (in a river), perpendicular to a bank, in one second.

If cumecs are the same for two pieces of water, then the same volume is passing the cross section BUT the cross section may not be the same.
Thus if one river is TWICE as DEEP, but the same WIDTH, it has TWICE the cross sectional area of the other and thus the VOLUME of water is passing any one spot in the DEEPER river is HALF that of the SHALLOWER river - ie the water flows past at HALF the speed (since the deeper river has TWICE as many "spots").

Yes - a lot of the bigger rivers in Europe have greater flowrates than the Vaal - either more cumecs (more water) or more flow velocity (same cumecs, but are narrower -> less cross sectional area = more flow velocity).

Correct...but these flies are FAR overkill on the Vaal...as you said, in their EXTREME situations..

I have tied up some extreme flies close to 4grams myself for the Vaal - when fishing turbulent, high flow waters.

This method is open to debate...line straight into the water is subject to much more head-on force from the water, as opposed to a line that is almost horisontal to the flow...in other words, the water is not trying to get through and past the line (as in the case with your vertical method), but rather is flowing with the horisontal line...less drag on the line. It's like...put your wading staick straigtht into the water, vertical...lot's of drag! Put it in horisontal, at an angle to the water....the drag goes down to bare minimum. I dunno if anyone understands what I'm getting at here, but trust me, it makes sense.
You may have less tippet in the water...but your line is subject to a lot more "pushing-force" from the water.

Hmm - complicated FLUID DYNAMICS & FORCE VECTORS!!
(Any other Chemical Engineers/B.Sc Physics-types out there who can help? It has been a LONG time... )

The shorter length of leader affected by the acting force of the water (force 90 degrees = perpendicular to leader = full force). Greater force per length, but less length.
vs
Longer length of leader affected by less than the full acting force of the water (force at say 135 to 160 degrees to leader), but with longer length.
Less force per length, but more length.

At what angle/length combination does the longer leader have less force applied than the shorter leader?
When I have the time, I will try the math...

[smallstreams.co.za]

Lost me at "Oh no"

[Michael]

With regards to the line drag as we discussed above...no need for math, just do this as a comparison:

While driving 80km/h...stick your arm out the window, and keep it vertical. The force of the wind has it's full affect on your arm. Now drop it down to horisontal or like 15 to 25 or even 45 Degrees or so...the force on your arm is far less. Hence...line at an angle into the water creates far less drag than line that is vertical.

Plus...with my method...you can cover a lot more water and river bottom than if you do it vertically.
Your bottom fly is in a strike-zone of a small area on the bottom, and the other two flies higher up in the water column. (One almost out of the water, depending on the depth...assuming you are fishing three flies).
Whereas in contrast, all three my flies are on the bottom, in the strike zone where the fish are...and I can cover the water in an arc...so I'm covering maybe 2 metres of river bottom at a time, for a full drift from above me to below my position, as the flies swing past.
And I can fish from very close to me, to quite a distance from me. (Less movement, further from the fish, less spooking).
You can only go maximum ten feet from you...then you have to move closer.

[dizzy]

With regards to the line drag as we discussed above...no need for math, just do this as a comparison:

While driving 80km/h...stick your arm out the window, and keep it vertical. The force of the wind has it's full affect on your arm. Now drop it down to horisontal or like 15 to 25 or even 45 Degrees or so...the force on your arm is far less. Hence...line at an angle into the water creates far less drag than line that is vertical.

Ok, so now.......
ask some like, RAMBO ( is good one), to stick his arm out the window. For some reason, he has less drag when doing this.
Perhaps its cos he has more mass?
Just messing with you!

[jock0]

Excuse moi Windbuks, let's not forget another scheduled rematch you have due, wouldn't want you to claim 'fatigue' because you had to fish against another old toppie.

I seem to remember the excuse that day going along the lines of "I didnt stop for lunch while you guys ate cold pies"

Thanks for the info on control flies everybody, even though it probably doesnt apply to the original topic, its is very informative. I know the benefit of tying "slim" heavy flies, but little tricks like using counter wound ribbing will certainly help me while I try and learn to tie. I have tried the preweighted partridge hooks and they are not for me, but maybe one day when my tying skills improve I'll give them another go.

How much difference does the material used for the dubbing make - I have seen a few materials branded as "quick descent" dubbing and surely these will sink faster than something like antron or cdc that trap a lot of air bubbles?

[GGY]

With regards to the line drag as we discussed above...no need for math, just do this as a comparison:

While driving 80km/h...stick your arm out the window, and keep it vertical. The force of the wind has it's full affect on your arm. Now drop it down to horisontal or like 15 to 25 or even 45 Degrees or so...the force on your arm is far less. Hence...line at an angle into the water creates far less drag than line that is vertical.

Ah, but to get the same VERTICAL height out of the window, your arm would have to extend 2^0.5 (square root of 2) ~ 1.41 times the length of arm originally out of the window (@ 45 degrees)...not really an issue in the car analogy, but is an inssue when you are getting a fly to the bottom.

Plus...with my method...you can cover a lot more water and river bottom than if you do it vertically.
Your bottom fly is in a strike-zone of a small area on the bottom, and the other two flies higher up in the water column. (One almost out of the water, depending on the depth...assuming you are fishing three flies).
Whereas in contrast, all three my flies are on the bottom, in the strike zone where the fish are...and I can cover the water in an arc...so I'm covering maybe 2 metres of river bottom at a time, for a full drift from above me to below my position, as the flies swing past.
And I can fish from very close to me, to quite a distance from me. (Less movement, further from the fish, less spooking).
You can only go maximum ten feet from you...then you have to move closer.

Mike, I fish under the rod tip when possible. The start and end of he drift do not have the flies directly under the rod, since they are up/downstream thereof. Whenever possible, the rod is vertically above the flies, rather than leading them with the rod.

Also, my MIDDLE fly is my heavy fly, so my point fly is on the bottom, with only the top dropper above (and sometimes this is where the fish want it...)

While fishing "on the swing", with the flies moving in an arc can be effective, I prefer not to do so, unless the fish want this.

Gary

[dizzy]

I seem to remember the excuse that day going along the lines of "I didnt stop for lunch while you guys ate cold pies"

Thanks for the info on control flies everybody, even though it probably doesnt apply to the original topic, its is very informative. I know the benefit of tying "slim" heavy flies, but little tricks like using counter wound ribbing will certainly help me while I try and learn to tie. I have tried the preweighted partridge hooks and they are not for me, but maybe one day when my tying skills improve I'll give them another go.

How much difference does the material used for the dubbing make - I have seen a few materials branded as "quick descent" dubbing and surely these will sink faster than something like antron or cdc that trap a lot of air bubbles?

I have to say, I don't enjoy tying on the pre-weighted partridge hooks either,
but, I did find, if you take a knife the wieght, make some small "grooves",
the material grips better.

Some folks use a bet of glue on the weight before tying.

[Scythe]

I'm not a big fan of the preweighted flies either, though it has to be said that it is a time saver if you can accept the compromise on not getting the fly exactly the way you want it ito shape.

The materials 'stick' or grip just as well if you lay down even a rudimentary thread bed over the weighting like per manually weighted flies.

[Michael]

I got a whole bunch of #10 scud hooks with lead pre-moulded onto them from Fishy Pete's when they were still going. I have long stopped using those hooks. You can't use a bead with them of course, and like Scythe says...you rarely get the shape you want.
The naturals on the Vaal have uniform bodies...no lumps in the middle, or "fat" bellies. In fact, their heads are a little smaller than the rest of the body (Referring to the caddis now).

Been fishing the Vaal now for the past 9 years I think, and it's amazing how the methods and flies have changed. We used to hit the Vaal, with a 9 foot leader, strike indicator right on top, and two flies tied new zealand style, and fished upstream nymphing. That was that. The first dropper fly was a #10 green rockworm, weighted and with a bead head, and the point fly was a maylfy nymph in brown or black 90% of the time, # 14 or #16.

The ultimate on the Vaal must be when you spot like 4 of 5 fish holding in water about 40cm deep, 15 or 20 metres from you...right next to reeds or a tree line...an acurate cast with a dry and small dropper, drag free drift over them...one fish turns and mouths the dropper or the dry...and the water explodes!!
*Salivating...*

[pieterkriel]

yes things has changed on the Vaal, but I still find fishing away from me a awesome technique, although now without strike indicator, yes what a feeling when you get that explosive take on a dry