24 replies to this topic
Posted 23 October 2007 - 09:09 AM
What causes a tight or wide action.? This question was posed to me by Skeeter Jones. I thought it was such a good question that, although it has been mentioned a few times, it has never really been aired here on TU. The following is MY take on the subject and I invite you all to add your own thoughts and arguments.
Several variables control the amplitude or width of the action or side movement of the lure. These are lip width, velocity, material density, lip edge shape (knife or rounded), body shape at the interface with the lip, depth of the body, ballast distribution, lip material, hardware, water temperature and what you had for breakfast. I guess I got carried away there, but to different degrees, they all have an effect. I will deal with them one at a time.
Lip width. The frequency or how many waggles per second that the lure performs is directly proportional to the width of the lip and the velocity that the lure is pulled through the water. It can actually be simply calculated. Look up Strouhal, Wikipedia covers it quite nicely. If the frequency is low or slow, the body has more time to swing from one side to the other and therefore will swing further or have more amplitude. If the width of the lip is halved, the frequency doubles and with half the time available for side travel, the amplitude reduces. So, keeping everything else constant, a narrow lip gives a tighter waggle.
Velocity. Covered mostly under lip width, if the speed doubles, the frequency doubles and the amplitude is reduced. At high speed trolling, the frequency could be 40 – 50 cycles per second, the amplitude would hardly be visible, the lure appearing to be a log being towed. But the fish attracting vibrations will still be present.
Body material density. The denser material introduces inertia, the reluctance of the body to move. This is analogous to pushing a heavy vehicle or better still, a boat. Once it is moving, it is easy to keep the movement and it requires considerable effort to stop the movement. Therefore, the heavier the material used for the body, the less the amplitude or width of movement.
Lip edge shape. Covered in a recent post, a knife edge lip will produce larger forces and all else being equal, more force means more amplitude.
Body shape at the lip. One of my favorites and has not been discussed before. As the water flows up the lip, it hits the body. Having now where else to go, it is forced out of the side. This greatly magnifies the action. The more the body shape blocks the flow, the wider the action. If the body to lip interface was streamlined, the forces and hence the amplitude would reduce. I experiment a lot with front mounted lips, therefore there is no lip/body interface. The action is greatly reduced, but still present. Many antique lipless lures have a notch cut into the built-in lip. this serves the same purpose as the lip/body interface.
Depth of body. Similar to the effect of inertia, if the body is very deep, having a large area, this will be more difficult to force sideways and will have a smaller amplitude or a tight waggle. If you require a wide action, a body with less depth would be desirable. This effect is also affected by moments (force x distance). If the deepest part of the body is in the same location as the CoG, it will have less effect on the action. A short oar is easier to operate than a long oar.
Ballast distribution. Splitting the ballast introduces moments. This is the lever principle of force times distance. The longer the distance from the centre of gravity of the lure to the ballast weight, the harder it is to move. The effect is the same as increasing the density of the body material. So a split ballast will result in a tighter waggle.
Lip material. A heavy lip material or thicker material is adding weight and has a moment back to the CoG as explained in ballast distribution. A thin, light material will produce more amplitude, a thick, heavy material will produce a tighter action.
Hardware. This is all about weight and introducing moments. The tail hook and split ring has the largest moment as it is the furthest from the CoG. If you want the widest action, use the smallest split ring practical or even remove the tail hook all together. For a wide action, if the belly hook is in the same location as the ballast, it will have zero moment and will not affect the action in any way, force x distance, force x zero = zero moment.
Water temperature. Picky, but it theoretically does play. The density of water changes with temperature, as we know when testing zero buoyancy lures. Colder water is heavier, more dense than warm water. Therefore, cold water will result in tighter action.
A combination of all the above defines the lure action. By tweaking the individual parameters, you can choose the action that you want. As for whether a tight waggle or a wide waggle is more desirable, I have no comment. Only the fish can answer that one.
Posted 23 October 2007 - 09:45 AM
Vodkaman, this is a big help to me. I've got a lot to learn. Thanks for the detailed response.
Posted 23 October 2007 - 10:48 AM
Vodkaman, very impressive. I will always find something to learn from you. I am also very interested to find out ways to determine the desirable action of a lure, as I think the lure's action is the most important factor in triggering the attack of the fish.
Nevertheless, I think I do not entirely agree with you on the subject.
For instance, I think you left out 2 of the most important factors in a lure's action, which are lip shape and lip angle. The distance between tow point and lip is also important. Perhaps you remember that I discovered some lip shapes that change almost completely the action of a certain lure. What I discovered since, is that the same lip shape can determine different actions on different shapes of lures. I can never tell what action a certain lip shape will have on a new shape of lure. I just hope that one day I will be able to guess that.
One thing which I think should be outlined is that the factors you have in view, may act in a different way in the case of lures with the tow point on the lip, compared to the classical crankbaits, with lips below the tow point.
In the first case, the tow point pulls part of the lip and the body, while in the second case the tow point pulls the body and the lip. I think theese are 2 different situations.
One other thing which I would like to discuss is your ideea about ballast distribution. You say that a split ballast will result in a tighter waggle. I don't know what "waggle" is, I assume it is a synonim for "wobble" (lateral movement). Your explanation takes into consideration the lever principle. You say that the longer the distance of the ballast from the gravity center, the harder it is to move, which is correct. But once moved, the ballast is also harder to stop, due to the same leverage principle. You say it is very hard to push a boat to make it move, but I think it is even harder to stop it.
As to the lip width, I can tell you that one of my minnows has a round lip, so the width is larger than the usual lip shapes, and it still has a tight wobble. So I think if you make wider lips, this will not necessarily result in a wider action. Anyway, I am not completely sure about that, I still have to experiment.
Posted 23 October 2007 - 02:34 PM
Nice clear exposition, Vodkaman. Along with Rofish, I also think the position of the line tie is always critical. I offer the following observations. 1) for baits with line ties on the lip, i.e., medium and deep divers with lip angles less than 15 degrees: An "average" position for the line tie is 40% of the distance from the lure body to the tip of the lip. Relatively small adjustments of that tie point toward the body will result in tighter, more erratic action. At some point, the bait will become uncontrollable and tend to spiral. 2) for shallow diving bass baits with line tie on the body (not jerkbaits): The strongest wiggle is almost always obtained by positioning the line tie directly on top of the lip. I have no varying observation on this since I ALWAYS do that and it is very rare to see a commercial shallow bass crankbait in different configuration. But it's worth mentioning.
Posted 24 October 2007 - 07:20 AM
Also need to consider shape of trailing edges which are (somewhat contrary to what would seem logical) more important than leading, and another picky one; depth relating to hydrostatic pressure.
Very clearly put though Vodkaman, and one I think all should reread a few times...
Posted 24 October 2007 - 07:34 AM
Coincidentally I have just tried reversing a lip on a blank, and seeing what difference it made to the same blank. I remember trying this, years ago, but had forgotten the result. Obviously the lip is not flat but curved (side to side), and the action changed from a wide snake like action to a very narrow barley perceptible slow action (very Rapala CD). Just thought I would throw this in for you Hydrologists to ponder. Pete
Posted 24 October 2007 - 08:57 AM
Thanks Rofish and BobP for your contributions to this post. As most of you will already know, I am writing this from an engineering point of view rather than from hard earned experience. I wrote the document in order to test out the applied theories and logic against responses from experience. Unless the engineering theories can match the experience then the engineering principles have been misinterpreted and I have to re-think.
Taking the points raised in the above replies:
Waggle. There is always going to be a terminology problem until TU introduces a glossary of terms. You are correct, I was referring to side movement. In engineering terms it would be called yaw, rotation about the Z axis. As a new member, I struggled for months with many of the words used on this site, I really could have used a TU dictionary.
Lip shape. This is a difficult variable to account for. A narrow lip can be compared with a wide lip and sweeping engineering statements made with confidence. But shape affects many things. The width of the lip varies, the direction of the forces on the lip vary, the amount of water that hits the body varies. The only way anything positive or definitive could come from an engineering point of view would be by filming in a fluids lab test tank. I would love to get involved with that idea, if I was sixteen again, I would be heading for a fluids course at college, lure design would make a perfect thesis subject. At the moment the answers to this enigma lie with experience, to which I humbly bow.
Same lip on different bodies. The tight or wide action is never going to be totally dependant on the lip. The lip is the engine for the action, everything else on the lure, right down to the Devcon only serves to dampen the action. It is just a question of degrees. Stick a sports car engine in a bread van and the action will be dampened somewhat.
Split ballast. The points made regarding the inertia of the ballast are of course true. It is hard to start the boat moving and equally difficult to stop it. But the lip engine moves on. The rate of oscillation generated by the lip is totally unaffected by what is happening behind it. The only factors that affect the frequency are lip width and velocity. As inertia increases, the lure has more difficulty in moving before it is forced to change direction. Increased inertia definitely dampens the amplitude or width of the action.
Tow eye location. I have save the most difficult until last. The eye location on the lure determines the angle that the lure swims. The forces below the eye generated by the water flow on the lip rotates the body nose down. The forces generated by the water flow on the body rotates the lure nose up. When the forces above and below are equal, the angle that the lure sits determines the dive depth. This up/down rotation or pitch, is centered around the eye. If the eye is positioned on the lip, as on a deep diving lure, the portion of the lip behind the eye is acting with the body. In theory, the same could be achieved by moving the eye back onto the body and reducing the lip size. This is probably contentious, but that is what discussion is all about.
The yaw, caused by the side forces from the lip, is centered around the centre of gravity and NOT the eye. Therefore, it does not matter where the eye is, it will not affect the yaw action. What DOES affect the action, is the angle of the lip at the balanced attitude. If the eye is moved forward, the forces on the body increase and the lure rotates nose up until a balance is once again achieved. The lip now presents less area and less vortex creating side length to the flow direction, thus less power is generated and consequently, less action. The maximum action is generated when the maximum lip is presented to the flow, this occurs when the lip is perpendicular to the flow. This situation is also close to instability, but that is another discussion.
Another factor that affects the action is the distance between the lip forces and the CoG. Applying the lever principle, the longer the distance, the wider the action. Inertial forces will come in to play though. There will be an optimum position for the ballast for the widest action which would be about half way along the body. This is convenient, as that is roughly where we would want to put it in order to statically balance the lure.
Posted 24 October 2007 - 09:03 AM
Clemmy, would appreciate some clarification of your statements regarding the trailing edge shape and the hydrostatic pressure.
Hazmail, I assume the concave face forward gave the wide action.
Do people (or more correctly, fish) prefer a wider or narrow action? I expect both each have their good days.
Posted 24 October 2007 - 09:46 AM
In my understanding, at higher pressure it is more difficult to create a given amplitude of vibration (oscillation). So at greater depth, greater hydrostatic pressure, less amplitude. Sound is harder to create underwater but travels easier through it. Of course, as I said, a minor point at reasonable depths.
The trailing edge matter: Water doesn't know what a lip is, nor where it starts or stops. Action is dependent on drag and the induced vortexes being shed. The body itself will have action, even without a lip. The most obvious would be a lipless crankbait designed for just such action. Of course one could argue that the body serves as the lip, for indeed it does. My counter to this however is that on a "normal" crankbait, the lip is just an extension of the body, a way to modify the drag on the whole.
Now think of a cone. One would think that it is more streamlined moving point first. More action if moving flat end first, as there is more drag, correct? But this is INCORRECT, which I admit is counterintuitive. Drag is affected more by Trailing edges/shape rather than Leading edge/shape.
So there is more drag on a point first cone, and thus more action.
Similarly, people shave lips to try to cut through the water easier, thus getting greater depth/rate of dive. They would be better served shaving the BACK edges of the lip, as it will cut the drag more, and not subject the lip to as much chipping...
Posted 24 October 2007 - 09:56 AM
I forgot to mention this is not relating to diving angle, which is a related but seperate subject. It also does not change the correct explantation of ballast location/ torque arms and axis of rotation...
By the way, I always thought of "Waggle" as side to side like a snake, and "Wobble" as roll like a rocking boat. I guess "Wiggle" is a tight "waggle"?? I think we all could use some clarification of terms...lol
Posted 24 October 2007 - 10:28 AM
Wiggle, waggle, wobble, that is precisely how I percieve the intended movement descriptions. This is were so much confusion is caused when dealing with this subject. Many people refer to wobble as a side-to-side movement.
As to the rest of your post, I am forced to retreat and think some more. I particularly like the cone example. I'm off to bed now, I am going to have nightmares about killer cones!
PS. Saved by the edit function! I totally agree. It is all about what is happening behind the lip. You could argue that, when swimming, you may think that you are 'pulling' your self through the water, when in fact, you are being 'pulled' through the water by the low pressure created on the back of your hand. It's a heavy thought and I have not convinced myself of the idea yet, but it has merit.
The cone, flat first, the vortex has less room to do its work.
PPS. Got out of bed to write this!
Regarding the pressure statement, I have two arguements against this idea.
Firstly, if the pressure had the effect of reducing the action, that would imply energy comming into play. Therefore, the angler would have to pull harder, this extra effort would be collected by the lip and would cancel out the resistance on the body.
Secondly, because water is incompressible, the water properties are no diferent than at the surface. Example, it is no more dificult for a deep sea diver to move around at a depth of 1000 ft than if he was working in the deep end of a swimming pool.
Posted 24 October 2007 - 12:17 PM
From that perspective, I agree that the hydrostatic pressure at a given depth must be equal on all parts of a lure, canceling itself out. Good point!
Posted 24 October 2007 - 10:03 PM
Vodkaman: Using 'Clemmy's' definition - Concave forward = Waggle and concave back = Wiggle, thats @ 50 deg to horizontal. Liked your posts too, great practical information - please excuse my rough and ready reckoning. pete
Posted 25 October 2007 - 10:10 AM
If warm water is less dense than cold water, affecting the suspending qualities of lures, why wouldn't it also affect the lure's action?
Posted 25 October 2007 - 12:06 PM
The difference is to minute to noticeably affect action.
See the table here:http://www.simetric.co.uk/si_water.htm
We are talking about 2 decimal points of diff for 10° diff in tempreture. Would make a diff for winter and summer suspention of lures but normally it's not apparent.
Posted 25 October 2007 - 01:31 PM
I'm going to try and post agin keep being told I'm not logged in. Webble, wobble waggle. Why dont we just call the side to side either one of the three. The movement (rotation)of the top(back) and the belly (bottom ) of the bait ROLL. I've seen post where someone is trying to explain the difference and they still use the same term for two seperate axis movement.
Posted 25 October 2007 - 02:07 PM
The romanian word for crankbait is "vobler", which I knew it came from the German language. Trying to see if I was right, I went to some on line dictionaries, but I could not find the word. I had the ideea of doing a search on the german ebay, and look what I found for the word "wobbler":
I also went to Wikipedia, and found out that "wobbler" is a synonim for "crankbait", (depending on the country and region)
But what is interesting there, is the fact that they say that crankbaits "swim with a side-to-side wobbling movement". Do you think it is possible that the original german word "wobbler" or "wobble" came into English language, and after a while it took the "waggle" form? If you say it is a crazy ideea, I would understand.
Here is the link:
Posted 25 October 2007 - 02:18 PM
Ro, I bet you are right. I see the terms as equal. A worm on .the table or a snake will wiggle to move, he is moving side to side
Posted 25 October 2007 - 03:15 PM
Ok i got a question here its simple i just wonder how many lures (hardbaits) have you made Vodkaman?