Fishing Lure Design

[TackleMaking]

Hello All,

I know this is a little off topic, but some helpful members in another forum suggested I post this in the aerodynamics forum...so here goes!

I'm working on a series of articles about designing fishing lures. More specifically, on how the shape & size of a fishing lure affects its underwater motion. I've come across some conflicting information concerning the effect of a crankbait's lip on the behavior of the fishing lure. (A crankbait is a fishing lure that floats horizontally in the water. It has a "lip" protruding from its nose at a downward angle. The fishing line is typically connected to the center of the lip. When the line is retrieved, the lip causes the lure to dive in the water and wiggle.)

I'm wondering if anyone could point me in the direction of information that would explain how the length, angle, width and profile of the crankbait lip would effect a) it's diving depth b) it's "wiggle" (wide vs tight) and c) it's ability to remain horizontal while traveling through the water.

I would truly appreciate any tips or resources that can help me with this section of my article.

Thanks,

- Erik Moore
erik@tacklemaking.com

 

[buzz41]

After having endured fishing as a boy in the company of a scientific fisherman who seldom caught anything, I still think of fishing as an exquisite form of punishment. Never-the-less, I remember my fisherman father's beloved "flatfish" and other lures - generally resembling what you describe. Some were polliwog shaped with a metal spoon shape near the front pointing forward and down. They would float, and when pulled, wiggle downward. So long ago.

Now, fishing with the boys, and a cold case of Goebels, that's different. Fish? Who cares.

Back to the question. Analysis of steady state fluid phenomena is hard. And, predicting non-steady stuff is beyond most, certainly me. But knowing the common mechanisms at play could help sort out things. One is vortexes. Da Vinci even made a sketch of them. Vortexes due to separation are most often associated with shaking or vibration. This is one possibility of what is happening at the front lip. Separation usually will produce a shed vortex, first in one direction and then the other. The area behind the lip also , obviously, is acting as a diving plane pulling the lure downward. The motion of the lure produced by the vortex will, in turn, influence the vortex generation itself. How tight this coupling is may determine the type of motion and how fast it is. Buoyancy and ballast - bottom heaviness - will be a factor making it downward directional. Certainly, hands-on experimentation by someone with a good aerodynamics background could produce some interesting insights. Just some thoughts. Hope it helped.

Anyway, all this fishing talk is making me thirsty. Pass me a cold bottle of Goebels. What! They don't make it anymore? I'm done with fishing.