Trolling into river currents.

[walleye express]

A question and my answer from another board. I know a lot of you guys fish the Detroit and St.Claire, so might have others thoughts on the matter.

Question:
when trolling into river current, how does it effect diving depth?

contributing factors to depth:
1.line diameter
2.speed
3.length of line out

for instance:
if at 100 ft. back a crank bait will dive 20 ft. with 10 lb. line at 2 m.p.h. in a current free area, will it still achieve the same depth trolling into a rivers current or will line drag cause the bait to raise?or will the current make it dive deeper?

im sure the amount of current has allot to do with this as well. IMO, i think the more(faster) current the shallower the bait will run because of line drag.

also, how would boat speed effect the diving depth?

would you troll slower in a river to reduce drag because of the added force of the current? what im saying is, if your trolling a 2 m.p.h. and there is a 2 m.p.h. current there would be a 4 m.p.h. force.

curious on your thoughts. thanks.

Edited by adam bomb 1/11/2006 4:55 PM

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get your mojo rising!
adam


My Answer:

Adam.

I'm guessing you won't find to many if any written conclusions on river currents and their effects on the dive curves of crankbaits. After over 20 years of using just river currents to work plugs for both Steelhead and Salmon from my Drift Boat and sled, I can tell you that working up a reliable dive table for such a thing would be almost impossible. And using differnt line weights would have little bearing on my conclusions. Currents by their very nature, especially in rivers, cannot be accurately estimated or expected to stay constant for long. I used to run Wiggle Warts the most for Steelhead using 10#, and 1/2 ounce Tot's for Kings using 20#. I've run lines as short as 30 Feet out the front of the boat in holes 12 feet or deeper, and they ran almost straight down from the rod tip in swift current. Yet would actually be pushed up as the hole played out at its end by the waters own deflection against the bottom. A rivers hydraulic dynamics are not even close to the way static neutral water acts against trolled crankbaits, and could not be measured with any repeatable accuracy in my view. The best a man can do without a measured added weight and a three way, is let out certain amounts and test it, or find the bottom and reel in a little as it happens. Capt. Dan.

[double trouble]

there are so many variables involved in trolling in a river current it may be almost impossible to predict their depth based on current.common wisdom would say that a static lure place in a current would dive to its rated depth.trolling adds speed and directional shifts. that can change the dynamics of the lure and temporarily deepen its dive ,but and shift in direction will make the lure unbalanced and it will lose its motion ,thereby raising it up.the best example i can give is a turn in a boat while walleye trolling. as the outside lures speed up some directional shifting takes place and the lure will go higher in the water column. remember also that some lures are less affected by this shift because of lure and lip design.a wider, heavier, larger lipped lure will lose less depth from a sideways current.a smaller, lighter lure will lose its balance entirely. this is probably why a skinny lure like a rapala or a thunderstick will come to the surface so easily when fouled.
line diameter has the same effect. the heavier line drag will make a lure shift direction and lose its balance .
the same occurs with boat speed. lures are designed to maximum depth up to a certain speed. if you exceed that speed they will "spin out" just like dodgere or spoons.
certain lures like reef runners, tots,hot lips, are designed for high speed.either their shape or lip allows them to attain depth at higher speeds. they also remain at depth durring shifts in current or sideways forces.think of most river lures. they are short with large lipslike warts, tots , or flatfish.you were quite right in your analisis of the effects of lure depth. i just wanted to add some background.