Vodkaman

I suspected that Bassrecords comments regarding the hook to shaft variance might be the case. This need not cause a big problem. If the hook load is multiplied by the point/shaft distance, this will give a number that allows a direct comparison. Slightly more complicated but do-able. This problem is going to exist no matter what method is used for testing. I was hoping that the hook manufacturers would have agreed some kind of standard pitch, apparently not. Regarding the round bend discussion. I was not referring to any variations in stiffness or strength due to the shape, merely that if the bend had an odd shape, the load would be applied further out from the shaft compared with a pure round bend. The greater offset would effectively apply more load. All else being equal, the odd shape would fail first. This does not mean that the hook performs less. The fault lies with the test. This is why I prefer the point test. Which brings us neatly to the start of this reply.

I think my problem is that I was using casting plaster as I already had a 10Kg bag in the workshop. I tried all kinds of release agents, the result was always the same, I needed a hammer to get the foam body out. This is soul destroying. I think I'll try the rtv next, when I get organised. I find that the expansion is considerably more than the double quoted on the bottle and seems to be related to how thoroughly I mix it. What diameter do you make your vent hole? Mine blocked and I ended up with an inch of flash all round. When I finally lick this foam s$%t, I'll have to post an article on how not to do it, should give everyone a laugh.

First of all I would like to congratulate all those members who have contributed to this fascinating post. Not a subject that I would normally have been attracted to, but the depth of knowledge and research shared has really grabbed my attention to the extent that I have invested more hours in thinking time and actual work than I care to admit, as I suspect have the other contributors. I am well and truly hooked, pardon the pun. For anyone searching for information on hooks or testing in general, this post will be a ‘must read’ in future. Anyone who delves into any subject to the nth degree could be accused of being anal. But just by being an active member of this very specialized club could all be accused of the same crime. This is what we do. Anything that one would wish to know about lure design etc can be found within these pages. If it is not written, ask the question and the information will be forthcoming by the bucket load. I take umbrage at being accused of wasting my time, not upset, just mildly irritated. This is not the first post that I have been involved with were someone feels the need to belittle the efforts of like minded TUists. Clamboni, I am surprised at your comment as all your previous posts have been very interesting and instructive, always worth reading. Maybe I am just being a bit touchy having just spent about twenty hours thinking about the subject and doing a little drawing. Respect anyway.

As this testing rig is only going to have limited use, I have kept the design as simple and cheap as possible. The design is flexible and easily adapted to other applications. I think the diagrams are self explanatory; there are no critical dimensions so I will let them tell the story. The only part requiring some explanation is the ‘metal plate’. Inside the upper hole is a small 1mm dia hole in which the hook point locates. In order to drill this hole, the plate may have to be bent over. This is not a problem and the plate can be flattened again after drilling. To enable the locating hole to be drilled means that the plate material will probably have to be at least 1.5mm thick, but aluminium plate will be plenty strong enough for the purpose. Alternatively, a thinner material can be hammered over to make a hook on which to locate the hook point. The original design was to enable both point and bend testing with the same plate. As mentioned earlier, SAFETY GLASSES. I have given a lot of thought as to what part of the hook should be tested, the point or the bend. In both cases, it is the resistance to bending that is being tested. In my most humble opinion I feel that the most useful and consistent method would be to test the point. As another contributor pointed out that the bend shape can vary dramatically from a round bend to a sharp bend under the point. Under testing, the round bend would register a much better performance given all other properties equal. This is because the load would be closer to the hook shank. It’s a lever thing (without getting too anal). The one constant thing for a given sized hook is the shaft to point distance. Additionally, if the bend was tested, I feel that determining the point of failure consistently from hook to hook could be a problem due to the barb snagging on the plate. True, the barb could be crimped, but this invasive operation could affect the result and the snag issue will not have completely been removed. In reality, the same properties are tested, the results of a round bend test will be double the point test, as the shank/point distance is double the shank/bend distance (there I go again). The point test failure point should be fairly consistent and is the moment that the hook slips out of the locating hole. Each treble gives three opportunities to verify the results, if they differ wildly then we will have to re-think the whole test method. I do have more ideas for test rigs should this be the case. The water load can either be marked by the litre, as one litre = 1Kg. or simply borrow the wife’s bathroom scales, I know you guys like your lbs n’ ozzes (1Kg = 2.2Lb). The actual load value is really of little consequence as we are only performing comparative tests between different types of hook. Results within 5% – 10% of each other should not be considered bad results if we are to avoid law suits, anything higher than this deserves mention. I wish that I could build it for you but unfortunately I am snookered at the moment as regarding a workshop. Good luck and report back.

I know it depends on the hook size, but what kind of load range are we looking at. Given a range of hook sizes used by all. This will give me something to work on this weekend. Stuck in my apartment with all my tools and no materials, even have a test pool! This is a useful project, if it can be designed for testing other aspects of the lure. For example, pull out loads for hangar wires in diferent materials, woods etc. The effect of opening the hangar hole, better or worse. A lot of questions could be answered quickly with the right rig, no guessing involved, just hard facts.

I think a valid point would be, do you load the bend or the point. I am thinking that the point would be a more realistic measure of the hooks tendancy to straighten, but in actual practise, the load is taken by the bend. As for the mechanical device, I am thinking of a water container, slowly filled. Easy to graduate with a marker pen, no moving parts and very cheap.

That is probably because the aluminium transmits heat very efficiently whereas POP is a heat insulator.

These are just my thoughts on the subject, as I have not successfully molded foam as yet, but still working on it. If you leave the lip on, the resulting foam lip will not be strong enough to take the battering of a rocky retrieve. If you mold the slot, my humble opinion is that you will have problems retrieving the cast without destroying the mold (my big problem). The best solution is to cut the slot after casting. My plan is to shape or flare the body out to the lip and mold it all in one piece. Whether the result will be strong enough to take the rocks remains to be seen. Has anyone tried this method?

I've just bought some scales that weigh to 0.1 gram intervals. Should be perfect for this application. I bought them from a head shop, didn't see any heads though!

Great fish, great release.

When writing post replies etc, of more than a couple of lines. Write the text in a word document save it for safety. The text can then be selected and pasted onto the TU message. A lot of members are already doing this. I have lost countless hours in retyping lost text due to crashes, internet freezes etc.

I designed a lip jig system for controlling the profile. But when I built and tested it, I found that their was no real advantage in accuracy or time saving. I found that the best method for controlling the shape is the glued paper pattern and sand to the edge of the line with a drum sanding bit (Dremel). For larger numbers, you will need to get a punch machined up. The problem with this method is that you cannot change your design once the expensive punch has been made. I would be looking at a small NC router set-up, capable of cutting A4 size (210x297mm). The lip shape can be changed at will and each change can be saved. May also be used for cutting body masters and master molds. Expensive, but if it is for a business it could be well worth it, always nice to encourage the tax man to contribute his share. I am seriously considering NC milling (or routering) now and I am no where near a business.

I thought of embedding my logo into the art work. Could be template or stencil. Just preliminary at this stage as I have nothing to stick it to.

For hand made eyes, the loop of wire (formed around a suitably sized nail) need only be twisted once or twice. As long as it is not straight, it will not pull out. The weakest link is the epoxy/wood connection. By making the hole larger, I mean a really sloppy fit. You are increasing the area of the contact surface with the wood, thus you are increasing the strength of the joint. I too would have been worried about the line catching on the crimp marks. Everyone here will tell you that, if your material of choice is balsa, then a through wire construction is the only way to go, if you do not want to lose the big daddy fish.

I bought a box of dremel bits, in there was a tapered file bit. The most useful bit in the box.

Well, I have finally arrived in Lapala land. It's hot as hell and the humidity is unbearable. I've taken six showers today. The journey took 24 hours door to door. Not too many problems apart from having to pay $120 to change the date of my year return ticket, as you are not allowed in to Malaysia unless you have a valid ticket out. So the date must be two months from the entry date. The ironic thing is that I will never use the ticket, as the job moves to Shang-hai, China in six months. The second ironic thing is that the Malaysian passport official never even looked at the ticket. I very nearly had a rant at the guy, but past experience of globe trotting enabled me to keep my cake hole clamped. The hotel room reminded me of Sweden, my last port of call. If the room had a couple of birch branches, it would pass for a sauna with a temperature of 42 deg! I eventually managed to hassle the desk clerk to fix the air conditioning. This is what you get staying in cheap hotels. Before Mr L jumps in to defend his territory, I have to say that this city (Kuala lumpur) has some of the very finest hotels in the world, I am just too cheap to spend the money. Do a google on Sunway Lagoon hotel and check it out, well impressive. I was wondering how I was going to find my old friend and taxi driver, Mr Bob, when he walked into the bar. He spotted me as he drove past with a passenger. He abandoned his car (and passengers) to greet me. Five minutes later an irate chinese guy entered the bar and started screaming at Bob, he told me 'got to go, he's my customer'! I start work tomorrow, I think, as I have not had confirmation of the post, but decided to take a chance. If it does not work out, I'll hop over to Indonesia and live there for a few months. Mr Bob is off to look for an apartment for me. I told him that it must have a test facility for the fishing lure studies (swimming pool). I heard rumours that the job is going to be shift work. This is ideal, as I will choose to do permanent nights. This will keep me out of the bars and I can get paid for doing some whittling too. If anyone from the company is reading this, I'm only joking! I'm going to have to sign off for now as the loud jingle jangle from the fifty or so screens in this internet cafe is playing havoc with my hearing aid! Hopefully I will be connected again soon. regards to you all. Dave

I think it is a great idea. For the same reason Tally puts the catchers in a separate box, they become special. I would sell the lure along with the picture to back it up. A cheap frame will cost next to nothing.

So the netting stays permanently under the foil? Excuse my stupidity, this is the first time I've really understood this process.

Clemmy. The fact that water is an incompressible fluid has bothered me too, in my pursuit of explanations of the behaviour of the hard bait. So, here are a couple of real life examples of the forces in motion. A sauce pan filled to one inch of the rim and stirred. The water at the edge rises and spills over, the water at the centre sinks down, but the volume is unchanged. The shape of the surface reflects the pressure differences through the vortex. If you throw some sand into the pan, it will gather at the centre of the pan. We have all witnessed debris being drawn into the plug hole vortex after washing the dishes, haven’t we? As for flight, there are two theories of flight. The first being the traditional aerofoil theory that you are referring to. It has applications in lure design, mostly body shapes and has never really been addressed. Another one on the list of articles that need writing. The second theory is that employed by all flying insects. Normal flight is only effective down to about 6 inch wing span, any smaller and the aerodynamic forces are not strong enough to sustain flight. Insects use vortex theory, the same theory that the lip on the lure employs to impart the side movements. The fact is that the pressure on the front of the lip is not what makes the lure swing from side to side, it is the low pressure vortex that forms behind the lip. The vortex forms down one edge of the lip at a time, alternating from side to side. This ‘sucks’ the lip from behind, from side to side. A web search on vortex shedding will explain all. I researched Reynolds numbers when I researched vortices, the only information to be gained from the Reynolds number is the minimum (and maximum) speed that the lure will swim according to the rules. This pans out at about half a crank per second. Experiments proved this fact, the lure kicks in at a certain speed.

Clarification. Re-examining these theories with drawings has been enlightening and educational to me and I hope at least some of you get something out of the brain strain (yours and mine). Diagram 1 shows the lure in its normal swimming orientation. In this example, a deep diving shallow lip and a suitable line angle of about 40 deg to the water surface. While the lure is moving, this angle remains constant and represents how deep the lure will swim (a discussion for another day). The diagram shows that when the lip forces below the tow line are equal to the body forces above the tow line, the lure is balanced. If the lure attitude is disturbed by a rock etc, the out of balance forces will quickly rotate the body back to its balanced attitude. This balance is pivoted about the line tie. As a crude example to describe this balance or equilibrium, diagram 2 shows a long stick with a brick tied at one end and an egg at the other. A length of string is loosely tied in a loop around the stick. The stick is threaded through the loop until it balances. The balance point is found to be closer to the brick than the egg, but still, a balance point is found. The brick represents the lip forces, the egg represents the body forces and the string represents the tow line (fishing line). If a side force (push) is applied to the brick, the stick will rotate smoothly around the string. This is how I believe the lure moves, rotating around the tow line. This is of course, a gross over simplification of what is actually happening, but the principle is close enough to reality and easy enough to understand, to make the theory useful. Next we add gravity to the theory. Diagram (3) is identical to diagram (2) only rotated through 90 deg. It describes the same stick loosely nailed to a wall so that it can rotate. The position of the nail is the same as the string loop. The experiment represents a view of the lure looking along the tow line (fishing line). The nail represents the line tie, the brick represents the lip forces and the egg represents the ballast. In true life, the egg represents a combination of various forces, including the buoyancy, ballast, hook, eyelet, hangar wire and lip weights. The ballast position is close enough to this centre of forces so that they can be ignored for the purposes of this exercise. If a side force (push) is applied to the brick, it will be noticed that the stick will stop in a random position, not necessarily vertical. It will also be noticed that virtually no effort is required to move the brick, this is because the brick is nailed at the balance position. Referring back to the original article, this represents the start of the tow line/ballast offset instability. At this point erratic movement of the lure can occur. For convenience I have called this type 2 death roll. This type is generally encountered on deep divers, but can be encountered when experimenting with rear mounted ballast, this is how I identified the instability. Erratic behaviour of the lure will occur with this geometry setup, as there is no force trying to keep the lure vertical. The lure could randomly flip over into death roll. If the egg is moved further away from the pivot nail (diagram (4)), the stick will swing around to vertical, with the egg at the bottom. This represents death roll, the lure swings around the tow line in a wide arc. If the egg is moved towards the pivot nail (diagram (5)), the stick will swing around to vertical, with the brick at the bottom. If the brick is pushed, it will return to the vertical, this represents stable lure action. Remove the egg and nail the stick at the new balance point. Re-attach the egg to the stick at the nail pivot. Once again, if the brick is pushed, the stick rotates freely, stopping randomly, not necessarily vertical. It will also be noticed that, as before, virtually no effort is required to move the brick, this is because the brick is nailed at the balance position. Referring back to the original article, this represents the start of the tow line/ballast instability. At this point erratic movement of the lure can occur. For convenience I have called this type 1 death roll. This type is generally encountered on shallow swimming lures, but can be encountered by experimenting with extremely low mounted ballast, an unrealistic situation. Erratic behaviour of the lure will occur with this geometry setup, as there is no force trying to keep the lure vertical. The lure could randomly flip over into death roll. Diagram 7 shows type 1 death roll, the ballast sitting roughly on the tow line. A shallow lure with a 70 deg lip is represented. The two lines of instability are drawn in. positioning the ballast anywhere between the lines will achieve normal action. Diagram 8 shows type 2 death roll, the ballast sitting on the type 2 instability line. A deep diving lure with a 10 deg lip is represented. Conclusions. If a new lure goes into death roll, the above theory will identify what type of instability you are dealing with and will offer up a solution. Method, while swimming the lure, make a mental note of the angle that the line makes to the water, while the lure swims roughly horizontal. Hold the lure horizontal in your hand and hold the line at its swim angle (as noted previously). If the line points directly (or just slightly above) the centre of the ballast, then type 1 death roll is the cause. Solutions to the problem include raise (or lower) the ballast location, raise (or lower) the line tie eye position, increase (or decrease) the lip size. If the ballast location is some distance from the tow line, this would indicate type 2 death roll. Solutions include; lower the ballast or move the ballast forward, raising the ballast would make the condition worse. Raise the line tie location or reduce the lip size. In both type 1 & 2 cases, the ideal solution is to move the ballast, as moving the eye or changing the lip will change the tow line angle and affect the swim depth of the lure. For prototyping, I would always give the first prototype an extended line tie eye for easy testing of the geometry. If all the above is true, then lowering the ballast on a deep diver should increase the action of the lure by reducing the inertia of the ballast, effectively making the lip forces stronger. This can be visualised in diagram 5, as the egg (ballast) is moved closer to the pivot nail, the effect of the brick (lip forces) becomes stronger, swinging back to the vertical faster. This is contrary to what has been discussed on TU before, including me. I firmly believed that as the ballast was lowered, the action would be damped out. For deep divers, the opposite is true, as the ballast is lowered, the action becomes wider. For shallow lures with steep angled lips, referring to diagram 6, if the egg (ballast) is lowered from this location, the inertia opposes the lip and the action is damped. The above theories fully explain everything that I have experienced while prototyping. But I have only worked on a limited number of lure setups, I have not done any work with deep divers. I invite you to test out the theories with any lures that roll out of control and report back. If you disagree with the above, say so. By arguing the different cases we will (hopefully) get to the truth.

No need to change the design of a steep lipped, shallow swimming lure, other than increasing the ballast. Just allow it time to sink to the depth you want.

Great article Blackjack. Looks like hunting to me. Thanks for making the effort and sharing the information. A complete breakdown of the lure geometry would be nice, but I am not cheeky enough to ask. What is your success rate for manufacturing this lure, if you make ten, how many would you expect to hunt?

Appologies guys. I will prepare some diagrams over the next few days. Don't get me wrong on this article. These are only my findings and are up for heated discussion. I just want to get to the truth.

There are many causes for hunting, I have identified and explored four. Those that I have not explored and have no explanation for (as yet) are body shape and split ballast, but from what has been written on TU, it is obvious that they are out there. 1. Offset eye. This was mentioned by Skeeter if I remember correctly, if not, sorry. The eye is bent left and right to fine tune the straight running of a new lure, but if an extended eye is bent even further, the lure will start to swim in a ‘zig-zag’ pattern. I did not pursue this form of hunting as it is not pretty and would expect a 95% return of sold lures. Referring to my recent post titled ‘death roll’. As the lure geometry approaches the ‘death roll’ configuration, the lure will start to ‘twitch’. Closer still, the ‘twitch’ becomes a ‘zig-zag’, eventually the lure blows out. The problem with this type of hunter is that a sharp tug on the lure would probably cause the lure to death roll. This can be a good feature, although it does not fall into the category of ‘under control’, the short jerk causes the bait to dart off in random directions and then resume its normal swim pattern. As was posted recently, ‘fish don’t swim in straight lines’. The second problem, as discussed by all those that produce hunters, is that the hunting ‘band width’ is very narrow, production runs are not practical, generally every lure would have to be tuned. 2. For shallow running baits, approach death roll case No1. 3. For deep divers, approach death roll case No2. 4. Hunting lip. This solution does not involve death roll or any other instability and so the lure is always going to be a runner. As for whether production runs are possible, I am in the process of mold making as we speak and hope to report back on repeatability in the next couple of weeks.

Many people have commented by post and PM that what I have written was interesting but difficult to understand. Explaining these theories is definitely not my strong point and I hold my hands up and plead guilty. One contributing factor to this sad admission is that all this theory is new to me also and I haven