I want to make a larger version of a needlefish and I have been thinking about how to upsize the plug while keeping the characteristics (sink rate, angle, etc…) the same. My first thought was that I could just use the same multiple on the dimensions and the weighting but then I started thinking back to some physics classes. After doing a little bit of reading on volume and buoyancy it seems that going up in size on all dimensions by a factor of 1.25 gives me nearly double the volume which would nearly double the buoyancy so I would need roughly twice the lead to offset the buoyancy of the larger piece of wood? I'm sure I'm still missing something.

Another, maybe easier, way to do it might be to keep the ratio of wood to lead the same based on the weight of each?

Personally I do it much less scientifically. I make a few of the new size and tape on wgt till it sit where i want it. Then i put the wgt in wire it and try it. I will then adjust from there. I might make a few sacrificial plugs but I figure that is par for the course. I leave the scientific stuff for numbskull he is so much better at
it than I. I just get a headache
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J, changing the dimentions by the percentage factor will replicate the design larger but as you state the weights have to be greater than the p3centage. I did my stubbys larger by 40% and increased weights 3 times,i.e. 7 gram to 22 grams tai, weight. Triple the belly weight too.

Personally I do it much less scientifically. I make a few of the new size and tape on wgt till it sit where i want it. Then i put the wgt in wire it and try it. I will then adjust from there. I might make a few sacrificial plugs but I figure that is par for the course
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When have you ever caught a fish on a needle?

JLH

I have not tried to do what you are attempting, calculate in advance the required weight based on volume changes, although it sounds like you are going at it correctly. Still, there are some other variables involved.....particularly lift...... which become important once forward motion is imparted to the plug. I'd expect the lift forces to increase as a squared function (i.e., proportional to surface area) rather than a cubed function (proportional to volume). I suspect the balance between lift and weight is what you are after, not so much the balance between weight and volume, but I know nothing about hydrodynamics so don't take the above as gospel. My guess is you need less extra weight than a simple weight/volume calculation would indicate.

That out of the way, I have some other thoughts about this issue.
First, needles are strange plugs. They all seem to work no matter how they are shaped or weighted. I suspect it has more to do with their long narrow profile than their specific action or retrieve speed.
Years ago I spent a lot of time figuring out how to make them swim which turns out to be unnecessary. Likewise I stressed over sink rates and sink angles/balance points which also didn't seem to matter (except for casting distance). I thought I was getting somewhere until I built a copy of an old Eelpunt needle that was Steve Shiraka's favorite plug (and a plug others had taken 50+ lb fish on) and found out the effing thing floats and comes in straight as a toy boat!

So now I don't stress it too much. On calm nights I throw lighter stuff, on rough nights heavier stuff. I'll carry a long one and a short one, a light one and a dark one but I no longer believe that for needles the specific action of what I throw means a lot.......which is why I prefer darters and swimmers but that's another issue.

Thanks for the input guys! I'm hoping to reduce some of the trial and error by getting as close as possible on the first build and then I expect to have to do some testing and make some adjustments from there.


That out of the way, I have some other thoughts about this issue.
First, needles are strange plugs. They all seem to work no matter how they are shaped or weighted. I suspect it has more to do with their long narrow profile than their specific action or retrieve speed.
Years ago I spent a lot of time figuring out how to make them swim which turns out to be unnecessary. Likewise I stressed over sink rates and sink angles/balance points which also didn't seem to matter (except for casting distance). I thought I was getting somewhere until I built a copy of an old Eelpunt needle that was Steve Shiraka's favorite plug (and a plug others had taken 50+ lb fish on) and found out the effing thing floats and comes in straight as a toy boat!

So now I don't stress it too much. On calm nights I throw lighter stuff, on rough nights heavier stuff. I'll carry a long one and a short one, a light one and a dark one but I no longer believe that for needles the specific action of what I throw means a lot.......which is why I prefer darters and swimmers but that's another issue.


I don’t know yet if I think action means a whole lot with needles. The ones I’ve done best with do swim nicely but I’ve also had some nice fish on a lighter version that I made out of basswood that comes in like a stick. I mainly focus on the sink rate and the angle that it comes in at when retrieved (the lift you mentioned) because it allows me to control the dept. I want to be able to fish them near the bottom and I’ve started building different versions out of lighter and heavier woods to give me options when fishing different areas and conditions. One of the advantages that I have found with building them myself is that I can build a version specifically for an area or conditions that I want to fish. Might be a lot of work for nothing but it's been fun playing around and trying to make the "perfect" needle for each spot and sent of conditions. I've certainly learned a lot about fishing them and why they do what they do through the process.

When have you ever caught a fish on a needle?

Hey my name is not sauerkraut

Bert and Ernie...........
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Jlh while increasing the size overall and needing 2x 3x the "weight" to get your new larger lure to swim/sink as desired. Dont neglect to try out differnt woods as they may provide you the swim/sink rates you desire without needing 2x -3x the amount of weighting. Sugar pine, maple, ironwoods as quick examples if that makes sense.
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Try scanning the plug then play with the zoom settings. The weight can be done the same so to speak. It's fun because you can really end up with some great results. Enjoy the experimenting.

Hey my name is not sauerkraut

I can attest that he's caught fish on needles! witnessed it with my own eyes - I think he even told me "Numby made this needle"!

In reality I think he actually just called you by your last name as opposed to Numby, but I'll leave that off this forum :)
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I wrap mine with strips of lead then I can easily adjust how much and where I want the weight... when the experiment is over I weigh the strips and proceed from there... I think the majority of my hits come as the plugs sinks...
as the Professor said.. all those calculation make my head hurt.

I wrap mine with strips of lead then I can easily adjust how much and where I want the weight... when the experiment is over I weigh the strips and proceed from there... I think the majority of my hits come as the plugs sinks...
as the Professor said.. all those calculation make my head hurt.

Hey Joe great to see you post. Have a Merry Christmas

Hey Joe great to see you post. Have a Merry Christmas

thanks Paul.... same to you.. works been insane 14 hour days ( no time to troll fishing web sights)since September ( pulled the boat and missed the entire fall run) at one point I worked 21 days in a row with out a day off...we moved 3 plants... still more to come in February... with this weather ..Looks like I'll be making plugs instead of ice fishing!

Thanks again for all of the feedback guys. I haven't started on this project yet but I'll report back on how it goes. Trying to get the plugs I know how to make done early so I can spend the rest of the winter tinkering around with some new idea like this.

Don't forget that raising the surface area also increases the lift or drag so to speak and the needle will have a faster climb rate. (Assuming it's tail weighted and comes in with its nose higher than the tail.
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Don't forget that raising the surface area also increases the lift or drag so to speak and the needle will have a faster climb rate. (Assuming it's tail weighted and comes in with its nose higher than the tail.
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This is correct.

For my last run of large needles I used D = Cd * A * .5 * r * V^2 as a baseline but if you do that don't forget to adjust density (r) for the anticipated water salinity.

Or you could just follow Ed's lead, toss in the water and see what happens :hee:

They are weighted to sit pretty level in the water but I bet the increased lift will still come into play. I went through about 18 different versions of an 8" needled before deciding what I wanted. I found that pretty small changes in amount of weight and the placement had a noticeable impact on how they fished. I figure if I can at least get close on paper before attempting to reproduce a larger version it might save me some time.

Like someone mentioned above your best bet is to digitally enlarge/scale it. If you have a template or master with the hook and weight holes marked send it over and I can shrink or enlarge it to inches or a percentage.

I promise I won't make a dozen :rotf3:


I think even if you do it this way you'll have some minor adjusting.

J, FYI. I increased my stubby by approx 40%. NORMALLY I use a total of 11 grams. With the 40% size increase, 53 grams got it to swim the way I wanted it.