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With small lures, members discovered that very thin fiber/circuit board lips were more effective than thicker Lexan lips in creating waggle action. The thinner the lip, the better the action. The reason for this has not been discussed much, if at all. It is all about the sharp edge. Water can flow around a round object with minimum 'peeling off' of the flow, thus minimum disturbance of the water. Conversely, flow cannot negotiate a sharp corner; it cannot change direction that quickly. This causes a low pressure area behind the edge of the lip. Water gets sucked back into this low pressure area and thus the vortex is born. At very slow speeds, the shape of the water flow is symmetrical, the same both sides of the lure. But, as the lure speed increases, a certain speed is reached were the vortices start to interact. There is not enough room for the vortices to exist independently so they take turns. The vortices start to alternate, forming one side then the other. This effect is called ‘vortex shedding’, a ‘vortex street’ or ‘Kármán vortex street’. This alternating vortex is the engine that drives the lure, causing the desirable ‘waggle’ or action of the lure. This also explains why a lure has a minimum speed before the action starts. The sharper the edge is, the stronger the low pressure area, the stronger the vortex and therefore the stronger the action. Larger lures in the range of 8” and larger will require a thicker lip in order to survive bouncing off rocks with all that body weight behind. But the thicker lip is not going to produce as much action as the knife edge lip of the 3” lure. The solution is to cut a chamfer behind the lip face. This reintroduces the knife edge and improves the vortex strength and thus the action. Another way to improve action is to make the face of the lip concave. This causes pressure to build up in front of the lip which further increases the strength of the vortex. Here is a video that shows vortex shedding, and the start transition explaining the minimum speed. Dave

I think the first cranks I painted were somewhere around 1995. My use of the internet was absolutely zero at that point. Just get to spraying....

As I understand the subject, the lateral line is the fish's ears, a row of sensitive pressure sensors along each side of the fish's body. Just like with our hearing were not only can we hear sounds, but with an ear on each side of our head, we can tell roughly where the sound is coming from. When a fish moves through the water, it is pushing and pulling at the water making pressure changes, just like when you shout, you set up pressure changes or waves in the air. those changes in pressure travel away from the source, gradually getting weaker until they dissolve away to nothing. it is the same in water except it is movement rather than sound. The vortex disturbance that our lure sends out create an image of something moving rhythmically through the water. An inanimate object would not send out such a sound wave, thus creating an image of something alive and possibly edible. Of course, the image may be the equivalent of a Keystone Cops video, but real enough to warrant further investigation. I hope this helps. Dave

Thank you for sharing the great idea, Dave. I'd like to add a small one to yours. First, thin circuit board lips are more flexible than the thick lexan lips. So, when we retrieve a crankbait, the thin circuit board lip is twisted to one side (right or left) by the pressure of the water. Then the twist of the lip turns back to the original state, and ths moves the crankbait waggle faster. This process will occur continuously every times the crankbait swim to one side (right or left). Sorry for my long absence and poor English.