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Vodkaman

Triple Point Hunting Theory – the Wild Thing

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This article offers up a hypothesis (unproven theory) of a triple point in fishing lure design that will result in the most erratic action usually associated with ‘hunting’, a zigzag motion, often observed in lures when retrieved at just the right speed. It is a complex and technical article, and as with a lot of my stuff; a difficult read. If you don’t understand any of it then ask questions, but don’t knock it, I am doing my best.

Triple point is most commonly known in the field of metallurgy; a particular combination of variables such as temperature, pressure etc. that enables a metal to pass from a solid to a gas directly, totally skipping the liquid phase. The three forms; solid, liquid and gas all occur at the same point, hence triple point.

I believe that there is a similar point in lure design. The variables that control this ‘triple point’ are the same variables that we adjust when designing any crank-bait lure; lip length, lip width, tow eye position, body shape, ballast location in ‘X’ direction (length), ballast location in ‘Z’ direction (depth). Buoyancy of body material and hardware location also play their respective parts as always. Also playing its part in the search for the ‘triple point’ is ‘resonant frequency’.

Regular hunting – I published the theory of hunting 9th April 2017 ‘Hunting Cranks - Theory, Design and Build’. Here I outlined what is happening when a lure hunts and how to achieve this condition. You could refer to the point at which hunting occurs as a transition point between pitch (porpoising) and yaw (waggle). But this is not entirely true. It is simply the point when the swimming lip angle reaches/passes 90 degrees to the water flow, at which point the lure stops waggling and starts to porpoise. The transition is where waggle and porpoising are mixed together.

This condition is easily achieved simply by making the lip too long and trimming back until the lure just starts to waggle. The transition is not a precise point. The position through this ‘transition’ that you trim the lip to, will determine the qualities of the hunt; slow wide hunt through to rapid shallow hunt.

Back in 2007 when I first started working on the hunting project, I did stumble upon the triple point totally by accident. I can only describe the action as wild. Unfortunately the lure was butchered by me to make another adjustment, but I was unable to reproduce the action. At that time, I had not discovered what was actually causing the hunt, let alone the triple point. I had theories that turned out to be partially correct, namely the transition between pitch and yaw. After seeing the ‘wild’ action, I also speculated on the triple point, but was unable to figure it out for a build.

Ironically, I had stumbled upon a lure with a slow ‘S’ motion rather than a waggle when experimenting with some weird designs. I didn’t figure out was going on, what was causing this lazy ‘S’ motion until yesterday. Actually not a transition like I suspected, but caused by resonant frequency.

Resonant Frequency (RF) – this is what causes panels to vibrate on your vehicle when it travels at a certain speed, causing that irritating ‘buzz’ that you can never quite locate. RF is also what keeps architects awake at night. RF can cause buildings and bridges to collapse. One of the most famous incidents involving RF was the Tacoma bridge disaster.

The frequency of the lure, the speed at which it waggles, is determined by the speed at which the alternating vortices form behind the lip, controlled by the width of the lip. A narrow lip produces faster alternating vortices, a wider lip produces slower vortices.

The ability of the lure to roll is controlled by the ballast ‘Z’ location (height). To understand roll, think of a pendulum, a swinging weight on the end of a piece of string. The longer the piece of string, the slower the pendulum swings. The string can be shortened so that the roll period (back and forth time) is extremely fast. The ideal length of the piece of string is that which gives a pendulum period equal to that of the lip vortices. This ideal pendulum speed is called the resonant frequency of the lure, and will give the best waggle/roll combination. At resonant frequency the roll and the waggle enhance each other, and this causes the lure to ‘blow out’, so not ideal after all.

As the length of the hypothetical string increases from the ideal length, the ability of the lure to roll is in conflict with the vortex speed, thus the lure roll is inhibited. There comes a point where the vortex period is 3X the roll period. At this point, the roll and the vortices are in line with each other again, and resonant frequency is once again achieved. But this time the roll period is 1/3rd the period of the RF ‘blow-out’ frequency. It is at this point that I believe the wild action occurs, when the period of the zigzag aligns exactly with the 1/3rd RF of the roll.

My next step is to prototype for this ‘S’ motion. I must then combine this with the regular hunt geometry. This combination should give me the ‘wild’ action that I witnessed all those years ago. This combination of geometry I would refer to as the ‘Triple point Hunt’, a combination of the tuned pitch/yaw transition with the 1/3rd RF of the roll.

And so, although Mark Poulson was correct when he said that he suspected ballast height may well be the trigger to cause an erratic hunt, the solution is actually to lower the ballast to find the 1/3rd RF, or even lower to find the 1/5th RF. However, this is not enough. The position in the pitch/roll transition must also be tuned to the 1/3rd RF. Once this balance has been achieved, the width of the zigzag will be enhanced by the 1/3rd RF roll, the roll will be enhanced by the vortex waggle, and the lure will really start to dance.

My intention is to build a prototype with an adjustable ballast, to tune in to the 1/3rd RF roll, and find the best ‘S’ motion. I will then adjust the lip length to match the hunting zigzag period with the 1/3rd RF roll. This should result in the ‘wild’ action of the Triple Point Hunter. Once the wild hunt is found, a body can be designed to contain the ballast. This is probably going to result in a lot more prototype attempts and a rather weird looking body.

Actually, when all the relevant periods are perfectly aligned, a wide, regular hunt should result, but if the periods are close and not perfectly aligned, then a wild, irregular motion should result. As with such a build, such precise alignment would be difficult, and so the wild action will be the most likely outcome.

From what I remember of the ‘S’ swimming prototype, there was no visible waggle, just the pure ‘S’ motion. In theory, if the periods are perfectly tuned, there should be a visible waggle 3X faster than the ‘S’ motion. More possibilities will be available by tuning to different harmonics; The lip waggle is the first RF harmonic, the pitch/yaw could be tuned to the third RF harmonic, and the ‘S’ motion tuned to the 5th RF harmonic. This would produce a really weird swimming action, but first thing’s first, let’s not get too far ahead of ourselves. Thinking about it, what I saw all those years ago, may well have been this 1/3/5 harmonic triple point hunt.

Dave

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Great write up, and I do think you're onto something.  Also, I think that is a very good plan on your prototyping.  By focusing on only 2 points to start it should be easier to fully understand the dynamics behind the respective behaviors.  By honing in the resonant frequencies you should be able to keep the respective behaviors isolated.  The end goal of the triple point will be very difficult as without perfect alignment of the frequencies, the inevitable overlap between various points will likely cause too much instability.  If there was an easy way to measure these frequencies it'd speed up the process significantly as then it could be done more mathematically.  The only question I have is wouldn't the hunting behavior cause an alteration of the resonant frequencies of the lures at different points of the retrieve?

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Tarheelfishing88 - thanks for your support and agreeing with me.

As for any frequency shift; the base frequency is the alternating vortices behind the lip. Keeping in mind that hunting is speed related, and so that is the frequency that the pitch/yaw hunt and the lazy 'S' frequencies will be tuned to. There is a fair bit of tolerance around the pitch/yaw transition, also around the lazy 'S' adjustment. Once these frequencies come anywhere near each other, things are going to start happening.

If this experiment was done in a university lab then yes, we could control the numbers more accurately, but I do believe this will not be necessary. There are simple mathematical equations for the alternating vortices, there are also very simple equations for pendulum frequencies. I am not going to go this route because I don't think the pendulum equations take into account the density of the fluid.

It is likely to be some time before I can start work on the prototyping, so I am inviting you, if you wish, to go ahead and feel welcome to experiment with this hypothesis and see if we can turn it into a proven theory. I just ask that you bring the results back to this page.

It is out there now. This has been an ongoing project for twelve years, and now I finally feel that I am very close to answering all the questions. Whether the predator fish will be impressed remains to be seen. You never know, it might just be too scary for them!

Dave

Edited by Vodkaman

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Dave, that is as great read.  I know enough about the things you talk about to follow along, but not enough to be able to design a lure to your specs.

I'm like you.  I made a lure that had a great X action, and that would move offline almost 2', run for a bit, and then move back, as the ballast shifted from one side to the other.  But I haven't been able to achieve that action again on a consistent basis.  Some lures move, some don't.  I've been able to get lures to move off line for a bit, and then move back, as the ballast shifts the center of gravity from side to side, but i think the ball bearings I have been using move too easily from side to side.  

Years ago, I had the chance to talk to Larry Dahlberg at one of Angler's Marine's Bass-A-Thons, and I asked him how to make a lure that hunts.  He corrected me and said "with erratic action".  Who am I to argue.  He said that he hadn't made any himself, but he'd heard of some builders who used liquid mercury as ballast, so it shifted as the lure moved.

I'm stuck inside right now, due to cold, wet, windy weather, so I'm in the process of making some 2.5 lures with different ballast locations.  

I'm experimenting this time with using a length of lead wire for ballast, instead of ball bearings.  I think the cylindrical lead might move more slowly from side to side, and create kind of a lag in the movement of the center of gravity.

I'll let you know what I, if anything, I figure out.

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Dave,

I'll give it a shot, and I'll keep you updated with any useful progress made.

 

Mark,

I think you're on the right track by first figuring out how to make the optimal adjusting ballast, and that is the direction I'm starting as well.  One thing that may help is going back and looking at the versions you've made that already have the action.  By comparing weight used, amount of movement the adjustable ballast has, and proportion of ballast that you made adjustable you may be able to unlock its secrets. 

It may take a bit of time to determine how much movement along the axis is necessary to create the desired effect and also the desired speed of that movement.  The other part of the ballast I'm trying to figure out is whether I want a portion or all of the ballast to be variable because that is going to partially determine the needed speed and movement as well.

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Here is the method for attaining triple point:

1 - build a simple lure with a non-hunting lip, a deep belly will be required. It may be better to make a simple prototype out of balsa dowel and mount the ballast externally for the first prototype, to give you an idea of the body shape to shoot for on the next build.

2 - Fix the lip with temporary soft glue. 60 degree shallow swimmer would be a good place to start.

3 - attach all hardware including hooks, otherwise the data you collect will be useless.

4 - You will have to vary the ballast position vertically, so I suggest fit a satay or cocktail stick, and wind thin lead sheet or solder. Temporary fix with soft glue.

5 - swim test. If the lure waggles normally, lower the ballast. Keep lowering until you achieve a lazy 'S' movement.

6 - experiment further with the ballast to see how much vertical tolerance exists and make a note of the mid/optimal measurement.

7 - fit a longer lip. Long enough that the lure no longer waggles.

8 - keep trimming the length of the lip until the hunt occurs.

Note - when creating a regular hunt, when the lip is too long, the waggle stops, replaced by porpoising. With the lazy 'S" movement, I have no idea what will happen. I strongly suspect the same as there will be nothing to swing the ballast.

Keep the first prototype simple so that not too much time is wasted. If my theory is correct, you should have a fish-able prototype by the third go.

Dave

Good luck, and let's hope my hypothesis is correct.

Dave

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Once you have the body shape, and know the depth to fit the ballast, there should be no need to go through the ballast adjustment. You will just fit a lip slightly too long by 2mm 3/32" and trim for effect.

From past experience building batches of hunters, the achievable rate should be in the high 90's%, failures will be due to rushing the lip trimming operation or incorrect ballast position.

If you change the wood density, you may have to prototype again, but paint and epoxy should have minimal effect.

Dave

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Love your work Dave :yay:, as for me, well I am going to go and sit in a quiet corner (for a week) and try and digest all this :huh:.

I think I have seen most of these zig's and zag's in most of the shapes I have made but to intentionally add all these attributes will be a work of art  --   SO can't wait to check it out.

As for the Mercury, I made a few about 10 years back with mercury switches (in tact) where the mercury could flow up and down the glass tube. I inserted these in various places in blanks and got some interesting results, BUT on reflection I later decided the pollution risk was not worth it :oooh:. BUT gee the weight/volume ratio was great to work with.

Looking forward to checking out the results from all.

Pete

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Amazing information , really annoying anymore to hear or see the pros on T.V. talk about how their lures are designed to hunt only to see the very typical crank bait doing the very predictable wobble . We are all excited to see what you come up with . It's funny how you say it could look " Weird " but we've all seen what this means in the fishing world , weird is the norm . Good Luck

Tommy

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Well, I took my second prototype with the sliding cylindrical ballast out for a swim in 10-15 mph winds.  It swam really well, and down to 6'+, judging by the weeds I caught casting off my dock.  But, although I was able to tune the line tie to get it to swim straight, I don't know if it really hunted.  When I held my rod up and swam it close to the surface, it looked like it might hunt a little, but I couldn't tell for sure.

I'm making prototype #3 with a shorter ballast piece, to get more lateral shift within the lure.  I hope having it 3/8" long in a 3/4" bore hole will make uneven ballasting more noticeable.

If #3 doesn't hunt, I plan to make Prototype #4 with a longer lip that I can slowly shorten, to see if I can get Dave's method to work.

Note to self:  It is hard to see how a lure swims when the water is muddy.  Doh!!!

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Mark - The muddy water thing is my problem too. If I crack this thing, I am going to have to find a swimming pool to make the video.

I hope you get your side-sliding ballast working, good luck.

Dave

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Mark, were you able to get the wide "lazy" 'S' movement with the lower ballast?  I think that's the big thing to gain from this first step.  That ballast change alone may not give you a hunting action like you'd be used to since you're not adding all of the instability you would get by raising it.  From my understanding, it'd be when used in conjunction with the lip method that you should really be able to see some results. 

I'm right there with you on water clarity.  That's one of the reasons why I'm starting with a 1-3' diver to start and with polarized glasses I normally can get a decent look at lure action at those depths.  Is it bad that I want a pool just to be able to test my crankbaits?  Anyway, I'm hoping to have the time to start a few prototypes over the weekend.

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Well, the wind died down, and now there's 18" of visibility, so I tried it again.

The moveable ballast lures with both 1/2" and 3/8" of 3/16 lead wire both moved somewhat erratically, but swam straight.  Those lures had a lip that extended out from the 2.5-like body 3/4".

I made a second pair of the same lure, both with only 3/8" of lead wire, since I thought it had more movement.   I put longer lips in these two, out 7/8", thinking I would file them down until they were just stable, but still hunting, as per Dave's method.

Lo and behold, the 7/8" lip baits both moved erratically from side to side by about 18",and swam straight back to the dock!  They are both hunters!  I lucked out first try.

At a fast retrieve, burning them back in, they both swam  straight to the dock.  When they began to rise at the end of the cast, they both began to swim to the right, but didn't blow out.   I think that has something to do with the angle of the line as they rise.

Dave, you are a genius!!!

I'll take some pics and post them in the hard bait's gallery.

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Mark - Thanks. You have always been an avid supporter.

As you hit the hunt by extending the lip without having to trim back, this means that you might miss the hunt on the next build. The lip trim adjustment is quite fine. I haven't documented how fine but I would say 2mm covers the whole transition.

I suggest 1/8" longer on your next build, long enough that the lure no longer waggles, and then trim back in small steps. Make an extra body (sacrificial prototype), continue to trim right through the hunt transition so that you can see what actions are available, and be able to recognize on future builds what stage you are at in the transition. This will also give you an idea of how much transition trim is available.

It is a real pain having to build a sacrificial prototype, but if you document the changes and lip lengths, you will learn so much.

It may be a good idea to go back to the ball bearing ballast. Ballast shift speed may be important now that you have found the hunt.

Once you have cracked the regular hunt, make a new prototype, lowering the ballast by 0.5", and again, trim through the transition.

Dave

Edited by Vodkaman

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Dave,

I have already cut out another set of 2.5 bodies, and plan to make them run much shallower.   The first set ran down to 6'+, based on the weeds I was hitting at high tide.

I want to get a shallower version to hunt, sort of like burning a chatterbait.  

I'll start with a longer lip, and work my way back to hunting.  

I'll also do a version with ball bearing ballast, once I've gotten the hunting action solved.

I'll even try lowering the ballast 1/2", like you suggested.

I'm putty in your hands Sensei.  Hahaha

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How fast do you crank your lures, say on a steady retrieve?

For a guide; my reel cranks at around 1m per turn of the handle. My speed is between 1 - 1.5 cranks per second.

The reason I ask is that I did some mathematics, and speed makes a big difference in the ballast weight position. The slower the speed, the lower the ballast has to be. The slowest speed that gives barely reasonable numbers for ballast position is 1.5m/s, any slower and the body shape becomes real deep and ugly.

I just want your thoughts. I actually have very little experience cranking, I just design them :)

Dave

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I can build a series of baits and make about 60% of them truly hunt and be retrieved at any speed withount blowing out.  25% run straight and true.  But 15% are basically worthless, and that bothers me enough that I stopped building them.  I got a few really good hunters out of the experiment, which I like and consider to be a worthwhile exercise as a hobby builder.  But hunting is all about making a bait swim erratically, and another way to get that is to bang your bait into and off of as many things as possible during the retrieve.  That is way easier to do than build hunters and on balance, I believe a true running bait retrieved like that can be as effective as your best hunter.  Player’s choice.

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BobP - I agree, a plain straight swimmer in the hands of an experienced 'crankist' with plenty of cover to work with, will be as good, if not better than any hunting lure.

If anything, this 'Triple Point' hunter will be designed for shallow swimming were there is no cover, such as the water that I fish.

But for me, the project has very little to do with fishing. It was all about reading a TU article back in 2007 which implied that hunting baits could not be built consistently. I proved that statement wrong by understanding hunting, and building a series of ten lures were 9 hunted and I mucked up the tuning of the tenth.

My current interest is based on an action that I stumbled across in 2007 and could not explain, also people wanting a more erratic hunting action. The Triple Point hunter will be the solution, a lure that erratically dances on a straight retrieve, and dances in such a way that cannot be emulated by a crankist with a plain lure.

Two new lures are going to emerge from this project; the Triple Point hunter and a second lure with a lazy 'S' action, neither action has been seen before. It remains to be seen if the fish will go for either, I think the TPH will catch fish, the Lazy 'S' possibly, but on a heavily fished water, it will be something new.

Dave

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Triple Point Hunting Harmonics

 

To understand the erratic motion predicted by the Triple Point Hunter hypothesis (unproven theory) you must understand the harmonics of the various movements.

Diagram – the grid (green) is marked in half cycles. Waggle (yaw) is colored red, roll is colored blue, porpoise (pitch) is colored purple.

The waggle (red) is the base frequency which roll and pitch are tuned to.

For a regular, straight swimming lure, the ballast never gets low enough to flip the roll to the 3rd harmonic, and so the roll oscillates at the same frequency as the yaw (waggle). When the lure is burned fast enough to hunt, the pitch hits a high harmonic (7th or 9th). This causes the lure to twitch but not visibly zigzag. As speed increases further, the harmonic will switch to a lower number, 5th then 3rd. These result in the zigzag that we are all familiar with, the 3rd harmonic giving a narrow hunt, 5th and higher giving wider hunts. As speed is further increased the pitch will hit the first harmonic resulting in pure pitch (porpoise action) with no waggle.

The roll can be tuned to these harmonics also, by lowering the ballast. But, the only harmonic practical to reach is the 3rd, after that, the ballast position would be too low to be practical.

The top diagram shows the pitch and roll tuned to the 3rd harmonic. You can see that every 3rd waggle, all the forces align giving a strong, regular side movement, but with smaller forces causing small irregularities with each waggle which should result in a slight erratic action.

If the speed is reduced slightly from this regular-ish hunt, the pitch will hit the 5th harmonic, shown in the bottom diagram. This will give a much wider hunt, and also, at each waggle the roll forces will drag the lure different amounts, only coming into true alignment every 15 waggles. This will be the truly erratic action.

Both the diagrams are Triple Point Hunting (TPH) actions. I will call these TPH-3 and TPH-5. I predict that both of these actions will be available with minute adjustments to the cranking speed, TPH-5 being the slightly slower and wilder action.

The diagram is only a 2D representation. BUT, I did mention that the erratic action that I saw back in 2007, the lure was also moving up and down. This is caused by the rotation of the 3rd harmonic roll whereas the pitch and yaw are basically in the horizontal plane. At each waggle, the roll is going to drag the lure up and down at varying amounts.

Dave

TU wave.JPG

Edited by Vodkaman
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Subscribing cause it's not like I don't have enough stuff to work on!!!! LOL!!!

This is a great thread guys - awesome info and cool to see your work.

 I gotta say - it's a perfect challenge for using 3D prints for prototypes.... you'd basically guarantee the bodies are the same each time and you could print 4/5/6 interchangeable lips to pop in place and test instead of trimming on the spot.... 

 J.

 

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Dave - You may be able to prove out your theory using a video analysis software.  I have had success determining the frequencies and amplitudes of waggle for different crankbaits and comparing them.  I use this free software: https://physlets.org/tracker/.  I video my lures by pulling them down a test tank connected to a tram on a track with the camera mounted to the tram right above the lure.  The software allows automatic tracking of a designated spot on the lure with a defined reference frame.  The software basically plots points on a time vs distance scale and creates an equation for the sinusoidal curve.  I don't see any reason why this couldn't also be used to track and plot roll and track and plot porpoising (from the side of the lure if you have a side window in a test tank).  Here is a video showing the use of the software: https://www.youtube.com/watch?v=ocLQFMMLIGw. You only need 1-2 seconds of video to do the analysis.

Edited by goolies
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Goolies - thanks for the software link, it looks really exciting for someone like me. I have downloaded and will have a play when I free up some time.

I have tested my first prototype; I did get some lazy 'S' motion, but apart from that, not much else. However, I know what changes to make to proto-2. The problem is that I am working with a 2" body, and my test pool only has a diagonal of 39".

I positioned the ballast too far forward and had to wrap some solder wire around the tail in order to level the body, but there was not enough room for the 70 degree lip to work. Next, I chose a parallel lip for proto-1, a bad decision as not enough roll motion was imparted to really work the ballast pendulum. Stupid really, as a big feature of the lure I remember; had a wide and angled profile.

I need to put proto-2 together more carefully. It will have a 60 degree lip angle and an angled profile. I will keep proto-1 separate, even though it  was built for easy modification, with adjustable ballast and push-in lips. Also, I might just make a full history video of the process if I am successful.

I will be taking my time so don't expect results tomorrow. A lot of thought is going in to this project, I will work at my own pace. But, I will bring you honest feedback as I do not want to waste anyone's time.

Dave

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Man, I love it when you engineers talk dirty like this!  Hahaha

Seriously, I can't wait to see/hear your results.  I'm going to make another version of my 2.5 shallow runner today, with the moving ballast more over the belly weight, to see how it behaves.  Of course, I probably won't get to test swim it until Friday, when it stops raining and blowing.  Right now the water's chocolate and I can't see down 6".

 

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