bbduc

Swimbait won't swim

76 posts in this topic

BBDUC- thanks for Raising this/these problems, you have opened up a lot of doors for us.

Because what I have made is not a symmetrical, I am finding only some of the rules apply (I always seem to make my life difficult). Because of the top curve on the leading segment, and weighting biased towards the front, nearly all I have made (3) tended to want to dive, head down, and then tending to roll.

I have changed the weighting from vertical flat strips (lead) to horizontal, which as all are saying keeps the weight as low as possible.

Ballasting (all segments) so that the lure is horizontal to the water surface.

Tapered the body (vertically) to reduce lower half buoyancy, so less ballast required.

Placed the tow eye very low and made it as small as possible (minimizing head movement) and used a loop knot instead of clips.

All this served to raise the center of buoyancy/gravity, which finally, it appears, let's this shape work

Thanks again, you have got us all thinking. I'm getting close, and hope this helps some other 'unconventional' builders. pete

Ballast.jpg[/img]

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Pete, From your post, do we assume you got it to swim and/or is the excessive roll still a problem?

Theory tells me you still have a roll problem.

Dave

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Dave - swims nicely, although I still have to permanently fix hook eyes and hooks.I have been mucking around with the placement of these too. pete

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Pete. The ballast is performing two functions:

1. When the lure is not moving, the ballast keeps the lure upright, as long as the centre of buoyancy is above the centre of gravity. The tow eye does not play. This is stating the obvious.

2. When the bait is moving, the ballast has to counteract the roll. The roll is caused by the water forces across the back, they impart a side force, causing the bait to roll. Because your bait is now being towed, the lever principle comes into play, force x distance. The roll energy is the force and the distance is from the tow axis to the top of the back.

This has to be balanced by the force x distance of the ballast. The ballast mass is the force and the distance is from the tow axis to the centre of the ballast.

In your diagram, the tow eye is in line with the ballast weight, therefore the distance is zero, so the ballast is having zero effect at counteracting the roll force.

Your design problem is the opposite of bbduc’s, your tow eye is too low.

If you fitted a temporary eye up the back a ways, it will probably start to swim without the hooks. Try attaching a twisted wire eye in a 1/16 dia hole. Have the eye sticking out from the body surface by about 1/2”. This will allow you to experiment with eye location, by bending the eye up or down.

Bbduc is correct, there has to be some movement for the vortices to work. With the eye position too high, the ballast suppressed the roll forces and stifled the vortex induced action. BUT, by bbduc increasing the speed, the roll forces increased, the ballast remained constant, therefore the action started to become evident.

Although your bait swims with the hooks in place, I bet if you increased the speed, it would roll again.

This theory may also explain why heavier woods make better swimbaits than light woods. The extra ballast over damping the roll, for a constant eye position, thus requiring a lower eye location with a lighter wood.

I’m sure that it is more complex than my over simplification and conflicting arguments are welcome, but this new idea fills a big gap in my swimbait theory and explains a lot. This is what I gained from this thread. Thanks to all.

Dave

Edited by Vodkaman

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Pete,

I was wondering the same thing about the bait rolling. My other thought when you said you added more weight, albeit lowered, to the nose to reduce head movement, wouldn't you want a little movement/wondering their to start snake movement and therefor opening up more surface on the second face to increase water resistance? Remember this is coming from a guy who 3 days ago had a nice glider of a swimbait. :lol:

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bbduc, that is a really smooth and fluid motion that you managed to attain out of your swimbait. I don't think I have seen one swim any better. Congratulations on your prototype.

I am one of the unconventional builders. It seems that I have the same problem. Mine won't swim. I gave my first one the bath tub test today and it just rolled over on its side at about a 45

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Dave - I see what you are getting at here: "In your diagram, the tow eye is in line with the ballast weight, therefore the distance is zero, so the ballast is having zero effect at counteracting the roll force.

Your design problem is the opposite of bbduc

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Pete, it is perfectly feasible that I could be way off base with this idea. It fitted in with holes in my theory, but unless it explains what actually happens in the real world, it is just hot air. So far, the idea does not look too promising. I am obviously missing something. I will keep working on the ideas.

I experimented with crank bodies with high curvature on the back/belly. The only explanation I can offer is that it is giving a kind of aerofoil affect. So the highly curved back is lifting the lure, pointing the lure downwards.

If you reversed the shape, it would hit the surface and stay there. So another arguement for amending the shape, that is if you don't want to to dive.

Dave

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BBDUC,

How did you come up with the thru wire design?? Looks like something I would see in a nightmare. LOL. What kind of wire did you use, and did you have a jig made up??? It sure does look good in the water.

Tony

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Dave , I added the weight to the back (1 full gm), and it is better, seems to 'swim' at an even slower speed. I swam it as fast as one can in a 5' bath tub, and it does dive /roll, but quickly sheds this tenancy, and rolls the other side and vice cersa, all the time snaking as well, should be interesting to test it in the real world of fish.pete

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BBDUC,

How did you come up with the thru wire design?? Looks like something I would see in a nightmare. LOL. What kind of wire did you use, and did you have a jig made up??? It sure does look good in the water.

Tony

Hey Tony,

The design actually was started with the body shape of the bait. I knew I wanted to have some sort of thru-wire and that's what I came up with. There have been many great ideas and versions here on the TU site, I looked at them and created a hybrid that fit the bill. I had the finished thru-wire skeleton sitting on my desk at work, some thought is was jewelry. Guess it is in a way. The wire is SS .062, not the easiest to work with in tight quarters. No jig, just a handful of various tools and even more patience.

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Congratulations on your prototype.

I am one of the unconventional builders. It seems that I have the same problem. Mine won't swim. I gave my first one the bath tub test today and it just rolled over on its side at about a 45

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This is how it looked with the weight and hardware in it but after gluing and clear coating, it was out of balance. I got way ahead of myself. And did it again when I re-weighted it. Now, it sinks and is still out of balance. All I could picture was that beautiful snaking across the water. I think that I may have to start all over again. At least I will have an idea of where I am going this time. One more thought when you look at this. I had been laying my weights in horizontally along the belly but I started thinking about Vodkamans example of twisting the baton with around the center of balance so I put it in this one vertically with the heavier part of the weight at the bottom of lure. I was hoping this would get the front section to start moving at a slower speed. It didn't move at any speed. Except when I stopped pulling the lure and it would then snake around and do a 180

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That weight looks way too high. I don't remember suggesting putting weight that high. Sorry! Do you have a link?

Dave

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At first glance, and remember I'm no expert but your weight looks to be a little high. I try to keep my weight on pretty much everything a build to the lower third. You may have to the lower the lead down right to the base of your bait. I would remove the lead and clamp the lure together and drill from the bottom up. Actually first I would take the lead out and get back into the tub and hang the weight until you find the sweet spot, then drill. The weight may end up right at your hook mount, if so no big deal, you can pour lead right around it but make sure its correct. getting the lead out at when you pour around the hook mount is not fun. Your line tie should work there. If you were to reshape the body take a look at a jpeg John Hopkins recently sent me, who btw has been a great help. I think this may help you.

– bob

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Edited by bbduc

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V-Man, you never suggested that. I was thinking about one of the posts that you made a long time ago in which you talked about a stick or broom handle with the weights out on the end of it and the weights in the center of the axis. I think it was when you were explaining the X-ing action of a crankbait. I was hoping that by turning the weight verticle instead of horizontal, that due to the less leverage required to rotate the weight and first section, that it would make starting the movement of the head a little easier and the other body parts would follow. I hope this makes some sense to you as to my reason for installing the weight verticlly. I actually am thinking, that I may just need to go to a slightly heavier more dense wood, and use less weight.

John

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Thanks Bob for the JPeg I think I am looking at this thing all wrong and am getting ahead of myself way to soon. I have a bad habit of the so called," counting my chickens before they are hatched". Am going to fiddle with this one a little longer then start on another one, same shape and size. Thanks again for the insight.

John

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John, I can see what you were thinking with the broom thing, but with swimbaits, usually too much roll is the problem.

Pit you finished it, but if it is not fishable, you might as well experiment with it. You probably won't be able to split it open now, so don't know what to say.

It is scary the difference a thick top coat makes. I have been caught out by this in the past. Now, when prototyping (basically this is all I do anyway), I always add a top coat, so that the tests are realistic. Also attach hooks and splitrings, they have a profound effect also.

When you start the next one, start a new thread with it.

Dave

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Pete. The ballast is performing two functions:

1. When the lure is not moving, the ballast keeps the lure upright, as long as the centre of buoyancy is above the centre of gravity. The tow eye does not play. This is stating the obvious.

2. When the bait is moving, the ballast has to counteract the roll. The roll is caused by the water forces across the back, they impart a side force, causing the bait to roll. Because your bait is now being towed, the lever principle comes into play, force x distance. The roll energy is the force and the distance is from the tow axis to the top of the back.

This has to be balanced by the force x distance of the ballast. The ballast mass is the force and the distance is from the tow axis to the centre of the ballast.

In your diagram, the tow eye is in line with the ballast weight, therefore the distance is zero, so the ballast is having zero effect at counteracting the roll force.

Your design problem is the opposite of bbduc’s, your tow eye is too low.

If you fitted a temporary eye up the back a ways, it will probably start to swim without the hooks. Try attaching a twisted wire eye in a 1/16 dia hole. Have the eye sticking out from the body surface by about 1/2”. This will allow you to experiment with eye location, by bending the eye up or down.

Bbduc is correct, there has to be some movement for the vortices to work. With the eye position too high, the ballast suppressed the roll forces and stifled the vortex induced action. BUT, by bbduc increasing the speed, the roll forces increased, the ballast remained constant, therefore the action started to become evident.

Although your bait swims with the hooks in place, I bet if you increased the speed, it would roll again.

This theory may also explain why heavier woods make better swimbaits than light woods. The extra ballast over damping the roll, for a constant eye position, thus requiring a lower eye location with a lighter wood.

I’m sure that it is more complex than my over simplification and conflicting arguments are welcome, but this new idea fills a big gap in my swimbait theory and explains a lot. This is what I gained from this thread. Thanks to all.

Dave

Dave,

Some time ago I set aside a swimbait that had too much roll to it. Well, after reading your theory above, I pulled the bait back out and intend to do some experimenting. Before I start messing with the weight I thought I would experiment with the tow point location. If I understand your theory correctly, the tow point should go up some but I will experiment with moving it both directions to see what happens.

Jed

Edited by RiverMan

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The eye is a good starting point. I would fit a temporary extended eye, so that it can be bent up or down, without having to drill lots of holes. Extend about 3/8", twisted wire.

Excessive head movement and roll is usually the ballast too far back in the front section. Split the ballast, move some to the front.

If the roll persists, move some ballast from the belly to the back (Pete's solution). This increases the innertia, which reduces roll also.

After each ballast change, experiment with the eye loop (up/down), as the final solution is likely to be a combination of all the above. Use external lead sheet first, before drilling lots of holes.

Change one thing at a time, so that you know what worked. I am still trying to understand all this too, so no guarantees or recrims. Most importantly, report back please.

Dave

Edited by Vodkaman

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Dave, You were right (again)

"1. When the lure is not moving, the ballast keeps the lure upright, as long as the centre of buoyancy is above the centre of gravity. The tow eye does not play. This is stating the obvious.

2. When the bait is moving, the ballast has to counteract the roll. The roll is caused by the water forces across the back, they impart a side force, causing the bait to roll. Because your bait is now being towed, the lever principle comes into play, force x distance. The roll energy is the force and the distance is from the tow axis to the top of the back."etc etc

I never doubted it mate, but just had to field test them in the real fish world of salt water. In the tub they were going O.K (varying degrees), but out there on the lake, they rolled - I'm thinking the problem is the slope of the head, this (I THINK) needs to be symmetrical and weighted low, as you say, get this right and the rest will follow - have been thinking of Dan's comment, so I am going to try a variation of that as well - I'm not going to let this beat me. We caught fish, but not on the three no swim "swim baits". pete

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Pete.

I went quiet after your "weight in the back" post. I needed to think about this one. I was not convinced, but there was a small arguement that worked, ie the innertia arguement. But the arguement against this idea was, that the CoG of the bait is raised, making the roll condition worse.

So Riverman. In light of Pete's comments, by all means, try the weight in the back (externally) as a last resort, but don't hold your breath. My money is on the higher eye position and/or split ballast towards the nose.

Dave

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I tested the lure this morning after moving the tow point both up and down. Moving it up may have helped some but very little.

Jed

Edited by RiverMan

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