Vodkaman

One thing I have forgotten; if the lure is breaking the water surface, then this complicates things and may make my analysis above irrelevant. Dave

JD_mudbug – Great comments, covered most of what I was going to write. You should follow his suggestions first, as my suggestions are purely based on theory. First a disclosure, I have never built a wake bait. The bait looks like it would swim nice without a lip, with the tow eye just below the chin as shown in the 3rd pic (end view). The lure attitude is determined by a balance of forces above the tow eye and below the tow eye, in other words, the force of the water on the back of the lure balance the force of the water on the lip. What I see happening, is the water forces on the lip force the lure nose down. This moves the lip passed vertical and so the length of the lip is effectively reduced as seen in the swim direction, this reduces the force on the lip. At the same time, the back of the body rises and so the forces acting on the back increase. The result of these forces means that the bait rotates/rocks nose up then nose down, and then the whole process repeats, resulting in the bait rocking up and down rather than producing vortices that will give you the side swimming action that you are looking for. Try shortening the lip, possibly by a lot, but do it gradually. If this does not work then angle the lip more forward, say 10° and adjust lip length again. As long as the lip is not pushed passed vertical then the lure will find a stable balance, and will generate side vortices. Once the lip passes vertical then it cannot reach a balanced state. I know, complicated. Not my fault Dave

Let me expand on the advantages of 3D printing of baits. Once you have a CAD model that works for you, it is little more than a push button exercise to produce more bodies. There are various materials available, but I will not discuss further here, it is up to you to research. The print is slow, but for a small crank bait, 4 or 5 could be printed per run on most budget machines. We are basically talking low volume production. The HUGE advantage is that you can produce lures that are impossible by injection molding and/or casting. Features such as concave lips, lips with sharp edges, external sharp corners. You can produce 3D pectoral fins as discussed in a recent post on sculpin fish, for that extra realism. If your intention is to one day hit the BIG time and get your lure injection molded, you can emulate the injection molding and check that the lure works before spending thousands on expensive tools, there is no money back policy on tools that produce duds. Dave

Several people have posted 'duplicator' machines, I myself have built a couple. Computer NC control is an option, but all the machines that I have seen are manual motor driven. Commercial duplicators are very expensive, in the region of $50K but I built mine for around $200, not brilliant, but I was very happy with the results. Try a TU search. 3D printing Is a viable option. I have designs, but I have not printed one off myself as yet. To do the job properly, you will need to master a CAD software to a reasonable standard. You will also need to get involved with densities, COV (center of volume) and COG (center of gravity), to have any chance of creating a lure that floats how you want it to do without a lot of tedious trial and error. I hope to source a 3D printer locally one day as I have so many projects ready for printing, not just fishing. There are local printing services that I have used, but they are just too expensive. Dave

The process to convert to STP, STL IGS or any other conversion format is basically a 'save as' function involving 5 or 6 clicks. Either his CAD program has the feature (most likely) or it does not. Either the process takes seconds or is impossible. Simple lure body shapes take only a few hours to create. But, a body with gill forms, caudal fin, dorsal fin, pectoral fins, eye sockets or domes, mouth shape, and anything else, don't even ask for scales, can take upwards of 50 hours CAD work. Half of that is figuring out how to do it. Once you figure it out, and do the work fairly regularly, you could get the time down to 20 hours. If I put that kind of effort into a model, I am not going to give it away for free. When asked, I could take one of two directions with my response: 1 - "You're joking, right!" 2 - "Sorry, my CAD system can't do it, or is very difficult." Obviously a nice guy (like me) and gave you option No2 Dave

The lack of response to this thread probably means two things; 1 - no one has tried it. 2 - no one thinks it is a good idea. My thoughts are that adding MBs to a 5 minute mix and then trying to apply it to a body, is a disaster waiting to happen. This is why Mark is suggesting a test piece trial first before potentially destroying a body. Regardless, I wish you good luck Dave

Blazing Saddles

Good decision to ask for help, and I hope you get it from experienced designers and builders. Unfortunately, I can only tackle this enigma from a purely theoretical place. Dave

Firstly, great work with your experimenting. There is so much information here, it is going to take several reads to soak it all up. The 'closer to rod tip' thing makes sense. You are dealing with an action that moves side-to-side, so as the lure comes closer, the offset angle from the centerline increases. Resin-MB mixes are literally just creating a pure wood alternative. The problem is that the wood alternative that you are creating is very dense, probably around 0.75g/cm³. The lightest material I was able to make with resin-MBs was 0.64g/cm³. So, if you can make a glider with heavy woods then you can make the same glider with resin-MBs. You will have to ask glider experts about that. That is all I have for now, but will likely return with more confusion Dave

I'm only an 'apprentice', so I am just going to follow you Mark, as you 'explore' the issue. You could try a Facebook search for the answer Dave

As I understand things, Createx is a T-shirt type paint and must be heat treated to fix it. Blowing to touch dry is simply not enough. You MUST fix with a hair dryer. Dave

In the gallery, NOT here! Dave

Oh no! devastating news. I had a lot of communication with Ben over the years, a marvelous personality and a great loss to the community. My condolences to his family. I hope they find TU and savour his contributions. RIP friend. Dave

T_man7 - nailed it Dave

Can you try it now and let me know if it works. YouTube have made changes and messed up the permissions. Dave

Here is the Big Ed video. If you require anything else, quote the page number and the post number on that page. I'll do my best to help. Dave

Yes. Vortices always want to be vertical, there is a reason for this but I cannot remember. tornadoes are formed by a horizontal vortex switching to vertical. So, if you provide a square(ish) boot then the vortices will form on the sides. Be prepared to experiment and prototype more variations. Shoot video and study the swim in slow motion. If the tail flips/twists as in the Shafteez video then you may have to reverse the tail. The rounder body may give you problems, but good luck with it. Always best to change one feature at a time or you will not learn what works and what doesn't. Dave

Correct, the reason being; Injecting polycarbonate or any other material as used in the technique for smaller baits does not work for larger baits. The material thickness required to get the buoyancy right, will result in sink holes and an extended material cooling time. So, for large baits, dense foams are the way to go. Dave

Very good thinking Mark. I cannot reply with any conviction. My first instinct is that the extension would allow the tail to rotate further until the resistance from the body trying to rotate stopped the tail and the vortex reversed. So, the result would be the tail traveled further but the body would still rotate the same amount. But, all of this discussion is highly hypothetical, unproven conjecture, just me applying what I have learned about vortices. But, if ever I was to design a paddle tail, this post would be high on my considerations list. Dave

I have given this problem some thought. I get my best ideas in sleep and this problem just gave me a rude awakening. Theory - If you tow a round plate behind a swivel then it will rotate in one direction infinitely. The reason being is that the single vortex is continually propagating as it advances around the disk, the vortex never finishes and thus vortex shedding never occurs to cause the vortex to reverse. The Shafteez video above is very enlightening. First notice that the tail is rotating back and forth over the back of the lure rather than underneath the lure as designed. From the start of the swim, the lure tail is rotated through 180° before the alternating action even starts. This means that the bait is already loaded heavily from one side only with a 180° twist, and this loading causes the lure to swim on its side. Even though the tail shape is close to circular, the vortex is terminated when the tail section reaches the limit of twist. A new vortex forms on the opposite side and the tail twists in the opposite direction. I cannot explain everything because the action changes with speed. At very slow speeds, the tail swims under the bait as designed. At medium speeds, the tail swims in a figure-8 shape. At higher speeds the tail twists 180° and swims above the lure. To stop the rotation, you have to abandon the circle lip and adopt a shape that naturally causes the vortex to shed and initiate a vortex reversal. This shape involves an inverted ‘V’ shape with straight edges, a bit like the front lip of a hard bait lure. If you want to troll a circle tail at the higher speed then reverse the tail design; point the tail up rather than the normal down, this will cure the lure swimming on its side. Y’all know that explaining is not my thing and I have given you some heavy explanations to think about, explanations that basically say that you have been designing paddle-tails wrong all your lives. I suggest that you study the Shadteez and any other paddle-tail swim videos very closely and make up your own minds. Some of you are not going to like this post, particularly as I don't do soft plastics. That is too bad. Dave

Photos and a video would be very useful, as your description offers us little to go on. You may be concerned about offering photos, but this is a perfect case were photos are justified. BUT, we really need a video of what is going on in the water. Dave

This sounds like a paint dipped tooth brush solution. Draw your thumbnail across the loaded bristles and make a mess. BUT, I have not painted since school, and very badly then. Dave

I got my 500th post badge but still working towards my 'rookie' badge Dave

As for Strouhal number, you have to figure out the value of 'S' to apply to the equation. The value I came up with was S=0.12 but this was before video and so not accurate. Video is your friend as the cycles are too fast to count and operate a timer at the same time. 'S' is a function of lip width, distance and time. Once you have a value for 'S', you can apply this to different widths to calculate the new frequency, or the retrieval speed to achieve a specific frequency. If you do a TU search for Strouhal, I am sure I have posted about this before. Dave

OK, I was starting to think that you were some scientist come here for amusement. An easy mistake to make is to think of vortices as separate from the rest of the water. The water and all the disturbances like turbulence, vortices, displacement, laminar flow and static, all interact with each other, think of it as a complete system. A predator say one meter away is sensing all the disturbance coming from the lure; the result of the body movement, the disturbance caused by the vortices. Among all that chaotic noise is the pulse of something alive. Place a mirror in a bath tub of water, and drag your finger or any object over, you will clearly see all the micro pressure changes. Run a knife blade and see the vortices, they are clearly visible but not as clear as the theoretical diagrams would have you believe. Dave