It's been a while, but life is finally settling down up here on the North Shore. I'm finally able to able to turn a few plugs as opposed to working 7/24....

so, I spent the afternoon fussing over three needle fish plugs.Trying to get the weight balance and sink rate right. From 2 til 5:15 when I had to go get a hair cut.

Set up a bucket of water with saltwater at 1.025 specific gravity, and dove in....

Two, I got to the point when they settle on the bottom, the 2/0 hook on the belly acting as an ever so soft support/balance point and the tail continues to suspend, plug perfectly level. Their sink rate is so slow, you can eat a sandwich and have a cup of coffee. Not the best for current of any substance. But I hope pretty good for beach front and rocks, where there are eddies of current that bring things in and out and up and down. I'm quite excited about these guys.

The other one sinks faster. Maybe 1 foot per second. I may try to shave a bit of the lead off the belly weight when I do the final assembly to slow it down a bit more.

I did notice one thing in common on all three plugs. I balanced them to find the center point of balance on a hack saw blade in my bench vice. But in the water, the balance point to get a flat neutral sink was almost always 1/2" or so in front of the balance point on the saw blade.

So, now I'm wondering about the Danny plugs I turn. Even though they aren't sinking plugs, is the balance/pivot point in the water different than the dry balance/pivot point. My guess is that it is. If you nail the pivot point, my guess is you get wobble. The question is for roll and stability (rips), do you shift the belly weight back or front?

Oh for a video camera and some very slow motion studies of about 20 different set ups.....

That is the difference between the center of gravity and the center of bouyancy.

That is the difference between the center of gravity and the center of bouyancy.

Sure is,,, it is based on Density,,,, usually the tighter the grain the more dense.

I did notice one thing in common on all three plugs. I balanced them to find the center point of balance on a hack saw blade in my bench vice. But in the water, the balance point to get a flat neutral sink was almost always 1/2" or so in front of the balance point on the saw blade.

So, now I'm wondering about the Danny plugs I turn. Even though they aren't sinking plugs, is the balance/pivot point in the water different than the dry balance/pivot point. My guess is that it is. If you nail the pivot point, my guess is you get wobble. The question is for roll and stability (rips), do you shift the belly weight back or front?

This is the difference between the center of gravity and the center of bouyancy. It is a complicated thing to figure out in a boat never mind a little tiny fishing lure.

So, if I have my plug floating in the water, all rigged, if I try to lift out of the water with my finger, there will be a point where it will come up balanced and this is the cb? If I'm looking for a totally neutral cg/cb, they should be the same?

So far on my needles, these two points get closer if I keep the body profile near the tail hook bigger.

What's your experience?

This is the difference between the center of gravity and the center of bouyancy. It is a complicated thing to figure out in a boat never mind a little tiny fishing lure.

You should try it in an airplane,,,,:huh:

Ok. I am trying not going to get to technical,,, here is a picture,,, I did it quick so it is not the greatest explanation.

Imagine that this is the same exact floating needle made out of AYC,,, Look at the way it balances and then sits in the water.... The actual CG is way aft of the CB. Obviously because of weight or Density of the lure. Hence Dynamically unstable.

Now action comes from the way the lure moves through the water based on shape and stability.

To make it simple you need to find the point of dynamic instability (Weighted aft) This point is the point at which the object will continue to move away from the stable point with the stable point being that of no action. That dynamic instability is what gives it its action.

add a lip and start looking at fluid dynamics.:spin::spin: and the way the water flows around the lip causing action.

I don't think you want your needles to suspend/sink level (unless you shape the nose asymmetrically to provide lift/or intend to dead drift them) . The ability to control depth of retrieve comes from the planing action of the body. The action of a needle (i.e., those that swim) comes from the shape of the first 2" and angle at which that shape moves through the water (think of a tin squid and you'll see what is happening). The speed you need to retrieve them is a function of the lift provided by the body angle/length, and the total weight of the plug.

As complicated as this sounds, in my experience it doesn't matter much..............fish seem to like needles no matter how they swim or sink and I think the profile and movement is way more important than all the other stuff.

Glad to see you back at it, John.

Hey John .. Glad to see you back .. I like your thinking ,, Nuts and bolts . I was thinking the same thing as Numby . Gotta add retrieve rate to the mix . You have to take them out and throw them ,slow retreive and see how they behave . I make one that I call "retrieve sensitvie " Basicly a slow sinker but rises and falls as retrieve varies. That I fish on a rocky beach (end of cast) in about max 12' of water.. Current ,same plug will just sit on top . Tough to make a bad needle ,weight wise ,, Its where you fish em .. I 'm making a small needle for when huge bass,that are on pin head sand eels and touching nothing eles , Chances of landing one is not as good,, because I had to down size hooks so much . I know that .. I don't really like fishing less than a 3/0 hook . The fish I'm targeting (not catching) I've been buying 6X lately also .. I don't know how those (Big Fish) Jersey guys catch large on Lefty size hooks ?? unless the fish is just inhaling the plug and on both hooks . once again you got me thinking again .. thanks .. Numby wants them to swim too .. I'm not there yet .. trying .

I think where I'm going with this is that ideally, I want to have the cg/cb be the same. That gives me a very dynamic instability and perfect balance. From there, I can tune the sink rate and attitude of the plug.

What got me thinking about this was some experiences I had last summer in two situations. One was on a beach north of here where I encountered large sand eels and bass feeding on them at night. The needle that worked best was quite neutral and rode very flat. Given that sand eels are weak swimmers and from what I've seen on film, tend to flutter and float and sink slowly to the bottom, this plug seemed to let me match that behavior the best.

The other was ocean front, rocky shoreline, little current, letting the plug suspend trying to imitate the short, hesitant movement of a bait fish as it swims through the water. In this situation, the retrieve that worked best was to put myself in the head of the bait fish. working it slowly and very erratically.

Although I don't quite follow you on the tin squid, somewhere in there, Numbskull, I think that you're right, there's a head shape that will add a natural swimming action to the mix. I'm going to have to play with that, too.

Interesting post. I rake sand eels and from my observations in shallowish water I find sand eels to be very fast swimmers and can move very rapidly from one submerged burrow to the next at lightening speed. They fly into the sand at reckless abandon. In deeper water they tend to stay in large schools for the strength in numbers theme and move together. I also have seen them sit horizontal, suspended, like you said. I like to make my needles sit sort of flat , suspend, because I fish in fairly sandy shallow water from a tin boat and I tend to twitch the lure more than reel it right in. The singled out injured bait look. I guess it has to do with where I am using the lure.

I've been chewing on the retrieve part of the equation, too.
Add in weight of the swivel, weight/length of line, angle of retrieve, etc. It gets interesting real fast. It sort of says, slight tail eight to me.
Yep. Tagger, I guess I just got to throw them. Only so much can be done in the "Fish Tank".

A needle that casts well, comes to the sutface easily and cuts a clean v-wake is all you could ask for and will catch as many fish as any other no matter how much theory and engineering goes into a plug.


Confidence in what your throwing and knowing just how to work it is probably the biggest factor in a plugs success as a fish taker more than anything else.

Although I don't quite follow you on the tin squid, somewhere in there, Numbskull, I think that you're right, there's a head shape that will add a natural swimming action to the mix. I'm going to have to play with that, too.

The curve on the underside of a tin squid makes the body act like a swimming plate. The weight of the rear of the squid gives it stability and sets the angle at which water hits the swimming curve. I'm pretty sure the same thing happens with needles. My experience is that the longer you make the nose, the less likely it is to swim. Still, as much as it pains me to admit it, I think Flap is right. He usually outfishes me by reeling his plug across the surface like a motorboat while he makes a Brrrrrrrrrrrrrmmmmmmmmm......brrrrrrrrrrrrmmmm sound.

I think where I'm going with this is that ideally, I want to have the cg/cb be the same. That gives me a very dynamic instability and perfect balance. From there, I can tune the sink rate and attitude of the plug.

not quite...... When the CG and CB are the same position you have total Neutral Static Stability. Very little to no action unless acted upon.

Neutral stability is Great for a metal lip,,, not so great for a needle your trying to swim on a retrieve.

Try not to get to deep in all this...


A needle that casts well, comes to the sutface easily and cuts a clean v-wake is all you could ask for and will catch as many fish as any other no matter how much theory and engineering goes into a plug.


Confidence in what your throwing and knowing just how to work it is probably the biggest factor in a plugs success as a fish taker more than anything else.


Bingo....

The discussion has helped me understand the physics of it all, which was what I was looking for. A few basic building blocks. It's been very helpful. From here, it's application and applying the art of building the plug and learning which needle is more appropriate for a particular situation.

Flap and Tagger, I'm going to have to give that v-wake more consideration this spring.

The curve on the underside of a tin squid makes the body act like a swimming plate. The weight of the rear of the squid gives it stability and sets the angle at which water hits the swimming curve. I'm pretty sure the same thing happens with needles. My experience is that the longer you make the nose, the less likely it is to swim. Still, as much as it pains me to admit it, I think Flap is right. He usually outfishes me by reeling his plug across the surface like a motorboat while he makes a Brrrrrrrrrrrrrmmmmmmmmm......brrrrrrrrrrrrmmmm sound.

I thought we had agreed to keep the Brmmmmmm...Brmmmmmm.. sound part our little secret?

Flap and Tagger, I'm going to have to give that v-wake more consideration this spring.

I know where Flap is coming from with the v wake,, wich is very effective in shallow boulder fields.. Just want too add I've done a bunch of fish 30 plus letting plug occaisionaly tic the bottom also.. Slow sink , very good to me . except fishing with Flap ,, then he out fishes me too ..