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Posted 03 February 2004 - 12:16 AM
In an effort to better understand crankbait design I put together a spreadsheet last night. I thought some of you might be interested in my findings.
I took various measurements of "minnow type" cranks to see if there were some definite parallels that could be drawn from one bait to the next which could then be taken to design and production of others. I would paste the spreadsheet here but it turns into a giant mess when I try and I am too lazy to fix the whole thing into neat columns. Anyway, here is what I did and what I found.
What I did:
I measured a total of 6 jerkbaits comprised of one Lucky Craft Pointer, one Bomber Long A, and 4 Rapalas. I would have liked to measure 20 more but this is what I had available to me. I took measurements with calipers to the nearest millimeter of body length, max width (side to side) and max girth (back to belly). I also took lengths of max bill width, and bill length. I determined bill angle with the use of a protractor using the center line of the bait as the constant parallel. With this info I also calculated values for body length divided by bill length and body width divided by bill width. I tried many other different ratios but could not see any consistent trends from these data and thus did away with them. I wouldn't bet my life on the measurements but they are close.
What I found:
1. The bill angle on the baits (keep in mind these are minnow style shallow runners) varied from 38 to 50 degrees.
2. Bill Width on the baits varied from 10 to 15mm, bill length from 13 to 19mm. In all cases bill length exceeded bill width.
3. The tow-point for all of the baits I looked at was attached to the body (not the bill) and below the horizontal center-line of the bait.
4. Body width was always equal to or very near the bill width. In the case of the Lucky Craft Pointer for example these numbers were 12 and 11mm respectively.
I think if a person had a hundred baits (or better yet 500) in front of them it may be possible to develop some very strong mathematical relationships for new baits saving us a considerable amount of time in the end. Of course there are many other variables to consider such as body material (plastic, cedar, pine, etc.), balast, wind direction, moon phase, etc., but it may be possible to find a range of constants for each of them.
So after this what did I find out? Put together a bait, cast it out, and see if works, lol.
Posted 04 February 2004 - 02:32 PM
I think that you were on to something here. It sounds like a lot of work, but if someone could come up with "standard criteria" and a way to measure it (like a 1 to 10 scale), that would be very interesting.
Posted 04 February 2004 - 05:40 PM
It's really not that bad, I did all of this in about 2 hours, most of which was coming up with the criteria I wanted to measure. The info I posted above only includes maybe half of what I chose to measure.
Once this is done it only takes maybe a minute per bait.
What I am thinking is that if we had enough information we could develop a "reference chart" for making baits. For example, say you wanted to build a minnow bait (jerk-bait) that is 65mm long and 15mm wide. You could pull out the trusty chart, find the length, the width, and follow these over to the appropriate bill angle, bill width, length, and tow-point. These values would probably not be "exacts" but rather a "recommendation" that falls within the center of a range of numbers tha have proven successful. This information could be developed for all types of baits, shallow, mid and deep runners.
I'm confident that if I had the baits I could put together the chart. We could ask members here to post measurements for their baits but this would greatly increase the liklihood for error. If Wal-Mart would just let me get into all those baits they have or better yet, perhaps all of you could mail me your baits, I'll return them I promise, lol.
One other thing that would be helpful is to take measurements of baits that won't work and see how if at all these baits fall outside of the range of measurements for baits that run...if that made sense. Many measurements/ratios and observations could be taken and added to the chart including "aspect at rest in water". Does the bait sit level, bill down, bill up, etc. All of these things would help the builder. So in theory, if a person developed a bait that hit the middle ground for all criteria in the chart, it would run, assuming of course good construction practices were followed, lip is straight, body even, etc.
And, finally, a "troubleshooting" section would help builders identify potential problems when they see a bait roll, not wobble/wiggle, not dive, etc.
Would be an interesting project to work on and potentially very valuable to us bait building guys.