I've got a good question for some of you about lead weight dynamics in the presents of water flow.
As a fisherman always trying and testing theory it seems to me that the shape of the weight can/could be altered to stay on the bottom hence a person might fish with less lead if this is possible.
The flat bottom is born at my house 🏠. I've played with this theory for quite a while, now I need experts to fill in the science part of my theory. I've been wrong before, and it's kinda hard to prove while you're fishing.
Below are the two shapes in question. Whenever possible if you anchoring and using bait the lead is just sitting on the sea floor. Let's disregard the rocks and square edge argument as is very rare to stick it stuck.
Thanks for your ideas and mathematics.🐙
Gary, I don't have one up here in the woods but long ago we started using flattened triangular weights with a hole through the middle flounder fishing, vs. egg sinker- low profile stayed on the bottom better Carolina rigging in modest current, and all types of surf fishing weights have flat sides similarly. Wheels roll, wheel chocks do not- go for it and I bet you reduce weight needed 20%. Always look forward to your R&D posts!
Thanks, it seems like a flat bottom will have square edges and resist rolling or tipping more than the round cannonball that is most popular here. We fish sandy, pebbles, mud mostly with bottom foliage.
Some folks have shown me some rectangular lead sinkers usually 2-3 pounds they like more than cannonball weights.
Line diameter, depth, and bait size also comes here into the constant equation.
Ok so my experience using heavy weights of different shapes is limited, I'm more of a free liner or split shot kind of guy. However my experience considering the effect of different shapes on drag is a bit more extensive. So with that said I'll throw my hat in this ring.
Let's start with some basics. Fluid dynamics in water is very similar to fluid dynamics in air. The difference of course is that water is denser than air so smaller changes produce larger effects.
Also we can agree on the basic principle that if an object in a flowing fluid (air, water, sausage gravy, etc) is moving, it's because the force exerted on that object by the moving fluid is greater than the frictional force between the object and the ground (let's not get into free hanging weights i am not gonna calculate the catenary of a fishing line I'm just not in the mood for hyperbolic trig today and this would be a much longer post) so to simplify, assuming weight is held constant the ideal shape is one that minimizes the surface area being affected by flow (drag) and increase the surface area in contact with the ground (coefficient of static friction).
A round weight is good because it minimizes the flat surface facing the fluid flow. But it also minimizes the surface in contact with the ground (for simplicity we're treating this as a hard smooth surface even though we know that's not true for a seafloor, so let's assume it isn't si king in. work with me here).
A square weight is good because it maximizes ground contact, but it also functions as a nice sail (ok hydrofoil) in the current with a lot of surface area for the force imparted by the moving water to act upon.
So if I was gonna make a "perfect" weight, I would go for a rounded pyramid shape with a flat bottom and rounded edges on top, or a smoothed out trapezoid. With the vote being for the rounded pyramid when you consider a sandy bottom because if it falls over with the base pointed away from the current that's just great: the water can roll around it much in the way a bullet passes through the air. If it falls over facing away, the force from the current would push it into the sand, which is even better.
I am not an expert at anything. Do not mistake me for one.
I could get into other shapes that see action in modern fluid dynamics, but I choose to focus on shapes that can be cast with a simple mold. We don't machine fishing weights.
Also we missed a golden opportunity to name this thread science and fRiction
If you are anchored, there are three areas of concern: getting the weight to the bottom,sticking to the bottom , and winding back up.
If you are in a reasonable amount of amount of depth and current, the larger force keeping the weight off the bottom will be the frictional force of the water against the cross section of line, not the current against a typical weight. There is less friction along the length of the line than across it, so the line orients horizontally which causes lifting force countering the gravitational force that makes the weight sink.
Any reasonably shaped weight will drop quickly if no line is attached. So achieving a shape that will drop quickly enough is relatively easy. Faster drop is still important though, and this would be achieved exposing the least amount of surface area on the bottom of the dropping weight, with a nice bullet nose to sweeten the deal. and a nice thin cross section that dod not have to orient is a given direction. I.e. a long cylinder.
The hydrodynamic forces against the weight on the bottom should be much less. There is a lot less surface area involved overall as there is no water passing under what is buried in the sand, and the current flow is lessened closer to the bottom. Folks that have scuba dived will tell you that one of the best ways to swim against the current is to hug the bottom. So once we hit the bottom, frictional forces on the weight will be a minimal part of the problem.
So this leads to three observations:
1. The thinner the line, the more you will hold bottom for a give amount of weight. The smaller the cross section, the less friction from current, the less lifting force on the weight. I think we sometimes under-utilize the strength of gelspun braid for deep water fishing. Thin is your friend.
2. What Gary is really trying to construct is a mini anchor with a bit of a curveball: at the other end of the anchor line is not a drifting boat, but a semi-fixed (anchored object). The goal would be to create a weight with a top section that will plow under the sand under tension, but the problem will be that the line will be lifting upward and probably a bit in the direction of the current, away from the boat. If you tighten the line enough to pull the top of weight toward you, the current will be working to lift and dislodge it, unless the weight can plow in so well that you have effectively set a second anchor for you boat, and might have to come off the original anchor to check you bait :) maybe the commercial long line guys have figured something out here. Or mebbe the worlds smallest Danforth anchor with a trip release :)
The pyramid style sinkers used for beach casting work because the water is moving in the same direction that the line is being tightened and the water is shallow giving you a flatter angle to hold the line. So I don't think this will apply to the situation at hand.
3. I presume that the goal of the lighter weight is less winding effort. If so, whatever shape you come up with better not increase the resistance too much when winding up, or you are back where you started from, or worse.
If we are talking about a lot of weight (16 oz or more), I would consider something long and thin (like a cylinder). It would bury itself in the mud efficiently, and could be would up more easily, meaning that you could actually wind more weight with less effort. It should be the most hydrodynamic shape for the drop that would not need to orientated in specific direction horizontally to achieve the least resistance. With the short moment arm it would roll less than Gary's disk for the same amount of lead. Flat sided versions would drift further on the drop, icreasing the amount of line in the water, so I would stick to round.
Quote from: JasonGotaPenn on August 31, 2020, 08:38:52 PM
[snip]
Also we can agree on the basic principle that if an object in a flowing fluid (air, water, sausage gravy, etc) is moving, it's because the force exerted on that object by the moving fluid is greater than the frictional force between the object and the ground (let's not get into free hanging weights i am not gonna calculate the catenary of a fishing line I'm just not in the mood for hyperbolic trig today and this would be a much longer post) so to simplify, assuming weight is held constant the ideal shape is one that minimizes the surface area being affected by flow (drag) and increase the surface area in contact with the ground (coefficient of static friction).
[snip]
A couple issues to consider:
The soft bottom is not a hard surface, so it is not a straightforward static friction problem, The object can displace or to pull under the surface of the bottom, which provides greater resistance. I would presume that soft mud or sand underwater behaves like some sort of quasi-fluid. So you have some sort of complex stacked fluids problem, not a straightforward friction problem, But I slept through most of physics :) I did happen to be awake when the prof noted that surface area does not affect friction. Just the total force and coefficient of friction.
Current and friction on the line makes this quite a complex problem. I guess it could be tackled with a fluid dynamics simulator, but once the results squirted out, I wouldn't be much more confident than when we started.
"catenary" is a new one for me. Just learned a new word :) It looks to me like it is the equation that defines the shape of a curve in a chain/rope between to fixed points. Interesting reading. Found out that an inverted catenary is the strongest shape for an architectural arch. Galileo, Bernoulli. Good stuff.
Curious if it could be applied at all to the situation at hand, as we are dealing with frictional forces that change based on orientation which would be different than the more uniform gravitational force from the classic cateneray example.
Nice to be able to talk a bit of science here :)
-J
Brilliant thread this is why I love the folks on this forum. My only other consideration that I would throw into the ring (no, I'm not going to say we all need to use expensive surveyors plumb bobs as weights to shoot straight down and implant in the bottom) would be the consideration of if the weight is spinning on the way down. Sure, we all use swivels, but most of them are pretty low tech unless you have popped for the pelagic ball-bearing varietie$. Getting to the bottom and holding the bottom is one thing: having a presentable bait once you get there is a whole 'nother story. - john
Well I made the classic mistake of poorly defining the boundaries of the system. You are correct that the main force acting upon the weight is that of the current upon the line and the bait etc. As opposed to on the weight itself. However one could argue that we would in effect be talking about holding those constant as well as the weight of... The weight. We're talking about varying the shape. But I failed to make that clear. But still you're correct that the force to be opposed is the not the horizontal force on the weight but the upward vertical force on it from the horizontal force placed on the rest of the rig. A catenary is ironically actually sort of close here though is not the most accurate description because the force isn't centered on the distance between the bottom of the line and where it leaves the water, its obviously closer to the bottom because that's where the bait is. And then you get into the force gradient of the current in the water column (again accurately mentioned but not by me) Thankfully we need not calculate it to acknowledge its there, and focus our efforts on the force in that direction. And I'm gonna have to think a bit more to have a meaningful idea. I'll have to come back to this.
However I will say that caution is needed because a shape that grips the bottom might not be ideal. I get hung up on rocks enough as it is.
You are partially correct re: surface area vs friction. A box with 3 different shaped sides would have the same frictional force regardless which side it slides on as long as the weight doesnt change. But friction and surface area absolutely are related. The reason a 5 washer drag system has more braking power than a 2 washer drag is surface area.
The concept of a catenary and hyperbolic trigonometry in general come up a lot in structural engineering when discussing load distribution. Especially tanh(θ) I believe I remember khan academy covering it well if you're interested in learning more.
But back to the topic at hand the issue is uplift. We could consider the cross sectional area of the line and bait etc and the speed of the current to calculate the minimum weight needed to keep a bait from drifting, but that's not the question. And i still say the pyramid shape (with attachment at the peak) is the most effective sinker shape for this application. But that's not a hill I'd die on.
This is lovely though. I enjoy being able to talk science with people. But relating it to fishing (at least in conversations outside my own head) is fairly new.
Still not an expert.
Thanks 🙏 to all comments and the great information. 🤳 Fishing can be more than fishing.
This post isn't about pitting us against each other. 👨💻 It's an odd subject that everyone may have to decide for them selves. I wish you all could fish with me in some situations and have some fun. 🧜♀️
As this gets interesting I want to add, I've used the sorta wide flat bottom weight to back down the current away from the boat, and others with good results. This said I,m good with fact that when tipped the flat top of the cylinder shape does add friction and the weight can be moved down stream more easily than the round ball. Some folks call this back bouncing. Typical in river fishing 🎣.
This is important if you can use it to your advantage. There's more hidden here.
The flat cylinder shown earlier is simply a cat food can mold. Da. Pretty easy for a start. Butt it may have something going on here that can help me.
The can mold can be poured to any height to make weight butt it's always a cylinder. I started with a 16 oz weight that was about 3/4 inch hi by about 2 inch wide and this opened my eyes 👀 as to something is going on here that I have to refine. Your cylinder shape idea makes sense when retrieving the lead/bait in stiff current. It's a sectional density equation that has variables. Hopefully heaven can wait.🤦♀️
Thanks for sharing your thoughts and information. Let's keep this going. It's free fun.🎣
I don't get it. Are we re-inventing the fishing sinker here? If you do not want the sinker to be pulled loose from the bottom by current then either increase the weight of the sinker, put tines on the sinker or add a weighted line ahead of the sinker so the lines pulls more horizontally and less vertically. If you do not want the sinker to hang up on obstructions then give it a rounded shape. Same as anchoring a boat or anything else.
-steve
Here's the "tine" thing. This one does well in surf/sand and might work on a muddy bottom. The tines will snap out of this position(pointing backward from what's showen) in case of a snag-up
Quote from: gstours on September 01, 2020, 03:31:05 AM
Thanks 🙏 to all comments and the great information. 🤳 Fishing can be more than fishing.
This post isn't about pitting us against each other. 👨💻 It's an odd subject that everyone may have to decide for them selves. I wish you all could fish with me in some situations and have some fun. 🧜♀️
Yep, Always tricky. The ideas need to compete, not the egos.
Getting back to the topic...
While it is a bit of a simplification, I think it is pretty well settled that frictional forces are independent of surface area. When the same amount of force is spread over a larger surface area, the larger set of imperfections on the surfaces are grinding against each other with less individual force. It ends up being a wash. Multiple drag washers in a stack is like dragging multiple blocks across a table. These are different pairs of surfaces that are not directly interacting.
Here is the first link that I came across from a university course, but there are plenty of others:
http://zebu.uoregon.edu/1999/ph161/friction.html (http://zebu.uoregon.edu/1999/ph161/friction.html)
"
In general frictional forces are independent of the area of contact although this is an empirical observation not a theory."
Designs intended to maximize surface area in order to increase static friction will probably be less successful.
Quote from: oc1 on September 01, 2020, 05:48:06 AM
I don't get it. Are we re-inventing the fishing sinker here? If you do not want the sinker to be pulled loose from the bottom by current then either increase the weight of the sinker, put tines on the sinker or add a weighted line ahead of the sinker so the lines pulls more horizontally and less vertically. If you do not want the sinker to hang up on obstructions then give it a rounded shape. Same as anchoring a boat or anything else.
-steve
Yes. We are re-inventing the sinker :) Or more specifically, deciding what sinker works the best on a deep drop in current. I don't think a new design is required. Choosing wisely means less effort to wind up.
I don't think anchor chains or tines will work for the reasons mentioned in my previous post.
-J
Following on Gfish suggestion, the Ulua(GT) fishermen in Hawaii use lead with copper/bronze wire protruding from the bottom and bent perpendicular to the lead axis, duplicating an anchor. The wire size is chosen so that it would straighten without breaking the line. Easy to do even making your own sinker.
Quote from: jurelometer on September 01, 2020, 06:25:48 AM
Yep, Always tricky. The ideas need to compete, not the egos.
Agreed. We are both trying to head toward discovering/establishing truth not dominance. Disagreement is healthy when well expressed.
Quote
Getting back to the topic...
While it is a bit of a simplification, I think it is pretty well settled that frictional forces are independent of surface area. When the same amount of force is spread over a larger surface area, the larger set of imperfections on the surfaces are grinding against each other with less individual force. It ends up being a wash. Multiple drag washers in a stack is like dragging multiple blocks across a table. These are different pairs of surfaces that are not directly interacting.
Here is the first link that I came across from a university course, but there are plenty of others:
http://zebu.uoregon.edu/1999/ph161/friction.html (http://zebu.uoregon.edu/1999/ph161/friction.html)
"In general frictional forces are independent of the area of contact although this is an empirical observation not a theory."
Designs intended to maximize surface area in order to increase static friction will probably be less successful.
I mean I don't entirely agree with the way you're presenting your argument, but in general I will agree that i was wrong to consider drag from the weight against the ground as a factor that could be increased by more surface area.
What one needs to consider is that the balancing effects that minimize the differences in frictional force caused by do hit critical points. Coefficients of friction usually have a range of validity. Making the comparison to something loosely related, think of terminal velocity, where an object in free fall's speed will be eventually limited by mass. even though, as Galileo demonstrated, a solid and hollow sphere of the same diameter fall at the same rate when dropped at heights that can be reached by climbing stairs. But with advances in aeronautics we've been able to see how that observation doesn't hold when they are dropped from the upper atmosphere. This is all to say that the effects of friction (and in fact many forces) aren't always linear, and the simplifications one would use solving intermediate level physics homework problems don't always hold in the real world. That doesn't mean they aren't useful for teaching the concepts or for calculating expected values in intermediate ranges.
And I am absolutely not trying to say any of this condescendingly, I'm shooting for a rigorous response because I've fallen short of expressing myself in previous posts. and i worry that text doesn't convey tone so i feel I should state that directly. I'm enjoying this discussion because it's forcing me to think about topics i haven't considered in a decade, and i appreciate you indulging me. However with that there's always a solid chance I'm getting it wrong.
Upper atmosphere? Who fishes from an airplane or rocket ship?? ??? ::) ::)
Rudy, reread the previous post. The concept of forces is the key, whether it is water or air, it is the forces that push and pull at the weight. Dominick
Quote from: Gfish on September 01, 2020, 06:07:04 AM
Here's the "tine" thing. This one does well in surf/sand and might work on a muddy bottom. The tines will snap out of this position(pointing backward from what's showen) in case of a snag-up
Short answer: Tines work when there is horizontal force. Here we have vertical ( lifting) force, so the tines cannot dig in.
-------------
Long answer:
Sinkers with tines need a horizontal pull to dig in. No good for our situation. My argument hinges on the claim that the horizontal force of the current on the line gets redirected to lifting force on the sinker, and the deeper the drop/faster the current, the greater the redirection. So any solution that will stick better has to resist vertical lift. If we think that this is not a valid claim, we need to come up with a better reason why the sinker won't stick to the bottom as well when the line is attached.
On a deep drop in current from an anchored boat, with the line free-spooling out as the weight sinks, the line will form sort of a "u" shape (more like a sideways "j"), with the current carrying the loop past the weight (sinker) as it reaches the bottom. Reeling up will pull the loop back toward the boat, which causes lifting force on the weight.
Whether the weight will break free when the direction of pull is away from the boat , straight up or toward the boat depends on line diameter, CoF between line and water, current speed, etc. Even if the line managed to tighten up pretty good and nearly straight line to the boat(which won't happen), the lifting force will be primarily be upward due to the deep drop. So there will be little to no horizontal pull.
I think that we have to remember why the weight is being dislodged in this environment (primarily upward lift from the forces of current on so much line). Making the sinker stick to the bottom when the current is causing it to be lifted vertically is hard to defeat mechanically IMHO, so the answer ends up being adding enough weight. At which point, we want the weight shape that drops the most efficiently (least amount of line to reach the bottom) and can be wound up the most efficiently (minimal water resistance while winding).
This is my argument against the cat food can shape. That, and I don't want to get a cat just so I can have some molds :)
I think that anchor chain style solutions would have to get pretty unwieldy to resist the substantial lifting force (unlike a normal anchoring situation, the current is working against us), but I have admit a lower level of confidence here.
Also, We should not focus on simply getting the weight to stick once it reaches the bottom, but look at the entire problem. We want the most efficient way to get the bait to the bottom and then back up again in this setting. With enough money and time, we could design some sort of lightweight frisbee shaped contraption that shot out a set of barbed legs that stuck to the bottom really well, and weighed only 6 ounces. Unfortunately, it would take a couple thousand yards of line and a quarter mile drift to reach bottom. Try winding that back up :).
My opinion is that cannonballs make a great all around sinker. They can be trolled, deep dropped, worked over sand or rocks. A great all-rounder. Sometimes less is more, especially on a boat. Don't like that they roll around the boat, and once they get up around 12-16 oz, they can start making dents and bruises. Sort of like a cannonball. ;)
I believe that deep drop fishermen often use long cylinder shaped weights, but I am not a deep drop guy myself. If I was looking for a specialty weight, I would start with whatever the deep drop guys go to. Especially if they are using a cylinder, as it lines up well with the science as I see it.
-J
My experience with this involves far larger lifting bodies, specifically submarines that are bottomed and how to keep them there. There are hydrodynamic shapes that alter the effective angle of attack in such a manner that they could be expected to assist a sinker to stay on the bottom while being acted on solely by the current and submerged long wave forces of water. Unfortunately, you would be fighting those forces all the way up and the harder you fought the stronger the effective angle of attack would increase in a downward direction. That and it would be prohibitively expensive to design and manufacture the mold.
I do believe that we can do better than a cannonball, I like the can food form because it minimizes the exposure of the weight to the current and the current on the bottom can often be quite intense. I do not like the cat food because you will fight it all the way up. At the velocities we are discussing and the level of complexity we want in a mold the optimum shape for minimizing hydrodynamic resistance upon retrieval would arguably be a teardrop; however, taking the operation into consideration, its efficiency is only slightly below that of a sphere. The sphere exposes more of the body to the water column and can be moved around easier than any other shape.
The best of both worlds would be a flattened sphere, such as the can that was pulled up from the side. The wider the circle used the better, but then you get into where are we going to store the thing.
Gary, I think you should cast the wire into the side of the cat food sinker and give it a go, if you can figure out how to make the sides round, so much the better.
The Man
The Man
Quote from: jurelometer on September 01, 2020, 07:27:35 PM
I think that anchor chain style solutions would have to get pretty unwieldy to resist the substantial lifting force (unlike a normal anchoring situation, the current is working against us), but I have admit a lower level of confidence here.
I was a land-based shark fisherman as a kid. The most annoying thing in the world was to get all set up for the night and then have the surf pick up or the sargassum move in so the weight no longer held tight. Taking out a bait at night was a non-starter. The easy solution was to clip another weight onto the line and try to get it to slide out as far as possible. It was OK from the pier or jetty but difficult from the beach unless you had an outrigger. Nonetheless, a little extra weight to keep the line down would always keep the bait from moving around.
Casting with some auxiliary weight up on the line is nearly impossible though. There is a type of surf fishing weight with tines like Greg shows but also having a long top wire. The long wire out the top makes it laydown so the tines will catch and sort of acts like an anchor chain.
https://buffalogapoutfitters.com/products/sea-striker-sputnik-anchor-sinker-4oz-long-top-wire-0029-2747?utm_source=google&utm_medium=cpc&adpos=&scid=scplpFARSS-4OZ&sc_intid=FARSS-4OZ&gclid=EAIaIQobChMIhqvDgpTJ6wIVEj2tBh2wMggbEAQYBSABEgI7QvD_BwE (https://buffalogapoutfitters.com/products/sea-striker-sputnik-anchor-sinker-4oz-long-top-wire-0029-2747?utm_source=google&utm_medium=cpc&adpos=&scid=scplpFARSS-4OZ&sc_intid=FARSS-4OZ&gclid=EAIaIQobChMIhqvDgpTJ6wIVEj2tBh2wMggbEAQYBSABEgI7QvD_BwE)
-teve
Dominick,"May the force be with you". ;D ;D
Thanks for sharing your information and thoughts 💭 . We are keeping a. Open mind a every person has a right to chime in. We don't all have to be rocket scientists to go fishing 🎣, sometimes just getting lucky overcomes doing things "wrong". I,m here to learn.
This may seem like and odd or dumb post butt there's some things going on when we make a drop.
Secondly let's narrow the weight shape and size to the fact that in the area I fish there is usually current.
This changes the assumption possibly that you are fishing strait down. When there is little or no current it easy to switch weights and make things easier for the drop and retrieving.
It's when the tides start running, everything staying the same you bait and sinker will lift up and as it can't go back anymore simply lift up. Lessening the line angle is helpful as well (another post with easier scientific explanation?) it just seemed like using as small of weight will make you happier and the possible shape could be improved from the cannon ball.
Yes the fisherman can help by choosing days when the flows are lesser, heavy leads are usually the complaint as to the point of throwing in the towel.
There's lots of good things happening here, and thanks Alan, for letting me in .👍
Big angle most certainly makes the problem worse. The longer, flatter belly in the line "flies" more. Its called kiting.
The Man
Quote from: gstours on September 02, 2020, 05:36:48 PM
Secondly let's narrow the weight shape and size to the fact that in the area I fish there is usually current.
This changes the assumption possibly that you are fishing strait down. When there is little or no current it easy to switch weights and make things easier for the drop and retrieving.
It's when the tides start running, everything staying the same you bait and sinker will lift up and as it can't go back anymore simply lift up. Lessening the line angle is helpful as well (another post with easier scientific explanation?)
This is what I was trying to describe. My apologies if it got too long or convoluted. Let me try (last time, I promise :) ) with a story and a diagram:
Gary says that he will take me fishing if I promise not to rattle on all day about fish vision and light waves. We anchor up at a promising spot with strong current in about 200 feet depth. I drop the sinker and start letting out line, but I was so excited that I forgot to tie on the sinker. The sinker (and bait) fall mostly straight toward the bottom, drifting a bit in the current. But the unweighted line is pulled away from the boat, and doesn't sink very far at all, with almost completely horizontal movement.
Hoping that Gary didn't catch this on video, I claim that I had a fray in my line, wind in, tie on a fresh sinker and try again.
This time, the pull of the current on the drifting line will be competing with the force or gravity pulling the sinker toward the bottom. The thicker the line, the faster the current, and the greater the depth, the more force will be coming from current on the line. If my sinker is too light, it will not be able to overcome being pulled up and along with the line. But Gary has set me up with a nice 2 lb sinker, so eventually it hits bottom.
A bit before (possibly) and after the sinker hits bottom, the line will form a loop downcurrent from the sinker. When I reel up, this loop starts to get taken out of the line, but I will never get a straight line from the rod tip to the sinker. It will lift off the bottom first unless I am using much more weight than is necessary to hold bottom without over-tightening the line.
As I tighten the line, I am mostly adding to the upward lift on the sinker
because of the force of the current on the line.(https://alantani.com/gallery/33/11927_02_09_20_2_24_48.png)
So anything that you do to the shape of the sinker to help it hold bottom in current, has to help hold against this mostly upward force. But if your design drifts or spins too much while dropping, or creates too much water resistance when winding up, you still could end up worse off.
I don't think that the bait load changes these basic issues much (just have to use more weight), but I will save that for another day.
Note that this is unique to anchoring. The interactions would all be different on a drift.
I could be wrong (wouldn't be the first time), but this is how I see it.
-J.
Taking out the bow in the line causing more lift is an astute point. My grandfather, erroneously, used to say that you laid enough line on the bottom to let the anchor hold position. As I studied hydrodynamics I realized that the chances of that happening are very slim unless you all but empty most spools by allowing the current to pull out line. There is a point where the line will get straight enough that this effect is diminished or eliminated, but as you pointed out if you can get there you are probably using way more weight than you need.
I see this as one of braid's unnoticed advantages. Its sensitivity is such that you can have a bow in the line and still feel what is going on with the bait.
The Man
Thanks Dave and Ron for this evenings enlighten ment. 🎣.
The example Dave shows here is very applicable, good graphics.!
As I'm learning from you I still have questions. As Ron implied that reducing the line angle from vertical to more horizontal should deminish the force of lifting the weight up. I agree with this and usually it's the first mending you can do on a imaginary drop. Generally this helps , butt there's a fairly small window of and how much this will work ok. I,d say about 25% of the time letting more line and working the bait back you will be able to fish with your chosen bait/lead if everything stays constant.....
Unfortunately things down there don't stay constant..... just look at the tide 📚 book.
I thought that a flat bottom low profile sinker may hold the bottom best because of the square edge sitting in the mud silt in comparison to a round ball. Maybe the lift up from the line is the demon here?
I,m hoping to make a flat bottom sinker with a side eye as Ron suggested before I,m done with fishing this year. Keeping the forces low may help, certainly the retrieving will be easier. Butt heaven can wait!
Quote from: gstours on September 03, 2020, 03:05:03 AM
Thanks Dave and Ron for this evenings enlighten ment. 🎣.
As Ron implied that reducing the line angle from vertical to more horizontal should deminish the force of lifting the weight up. I agree with this and usually it's the first mending you can do on a imaginary drop. Generally this helps , butt there's a fairly small window of and how much this will work ok. I,d say about 25% of the time letting more line and working the bait back you will be able to fish with your chosen bait/lead if everything stays constant.....
I am not sure that is what Ron was saying, but he can clarify.
To get to the same depth with less acute angle, you have to let out more line, and the more line that you let out, the more lifting force that the current has on your sinker. And I think that the U shape curve will still be there on the sinker side, so you will still end up with vertical lifting force on the sinker. My guess would be that you would end up with more force, still in an upward direction. No free lunch in physics.
But getting back to the original question, even if you are right, the general shape of the curve in the line and the vertical lift on the sinker should still be roughly the same. Modifying the shape of the sinker to resist a horizontal pull in the mud won't help if there is little horizontal pull.
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I thought that a flat bottom low profile sinker may hold the bottom best because of the square edge sitting in the mud silt in comparison to a round ball. Maybe the lift up from the line is the demon here?
Yes. That is the demon if my theory is correct.
The flat bottom/low profile sinker will sink slower and be harder to retrieve. It might suction on the bottom a bit, but I am not sure how it would much that would help. It won't plane up too bad if you lose bottom momentarily, so that is a positive.
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I,m hoping to make a flat bottom sinker with a side eye as Ron suggested before I,m done with fishing this year. Keeping the forces low may help, certainly the retrieving will be easier. Butt heaven can wait!
Very similar to a dollar sinker. These are not used for drop fishing for a reason. These will drift more on the drop and have a tendency to spin. Once they lift off the bottom they will plane up a bit, and are not good at catching bottom again.
I could be wrong, but if I was a gambling man I would not be betting on any of the cat food can designs, pyramids, or tines. I would take whatever drops the fastest without spinning and is the easiest to wind. Or just use a cannonball so I didn't have to carry too many different sinkers.
I would suggest to also try a longer cylinder or torpedo shape. Torpedoes (and submarines) must be shaped that way for a reason. Easy enough to pour something in 3/4 or 1 in pipe. John's (Brewcrafter) plumb bob shape is no a bad idea either. It might manage to bury itself a bit, and will drop and retrieve nicely.
Always enjoy your experiments. The field testing is where we find out what really works. Theories are just for making up the short list.
Glad that you liked the diagram. I made the sky grey so that it would look familiar :D
Quote from: Ron Jones on September 02, 2020, 11:10:58 PM
I see this as one of braid's unnoticed advantages. Its sensitivity is such that you can have a bow in the line and still feel what is going on with the bait.
I agree. We can fish differently with braid. Also, we can often get by with thinner braid than we use, which is already much thinner than mono. Shrinking the line diameter shrinks the force from the current (proportionately?)
-J
It's sort of weird that when you lift the pole, the weight is pulled away from you. Not pushed away and not pulled toward you, but pulled away from you.
The profile of the line perpendicular to the current is the line diameter multiplied by the depth (but perhaps not the amount of line out). Knowing the area of the line profile and current speed, and with all the forces being upward, it seems like it should be possible to calculate the force and, thereby, the amount of weight required to resist the current. Whether it's theoretical or empiriical, it seems like there would be tables or equations or guidelines or something for this.
Quote from: jurelometer on September 03, 2020, 08:01:35 AM
Shrinking the line diameter shrinks the force from the current (proportionately?)
-J
When they calculate wind load on a sail the wind speed is squared.
-s
Yes i smiled when I learned a new word from mr. Ron.
as·tute
/əˈst(y)o͞ot/
adjective
having or showing an ability to accurately assess situations or people and turn this to one's advantage.
"an astute businessman"
As i re read Rons reply on letting more line out I was not sure if I agree butt thats why i,m here. Thanks everyone for chiming in as we can be civil and still try to understand and be helpfull. ;)
I,ve found by experience that letting out more line can be helpfull to hold the bottom. That said it seems like the line angle and its lifting power is a clue to something here.... I also agree that this will only help if the weight size is close to the minimum size that will not get swept downstream. There are some hidden forces at work here.
Another part of this lead weight delima may be bait size and shape. I like to use an led light at times butt thats more drag. A spin n glo winged body is popular here to make motion, and or vibration. Butt my style is a large 12 size musky spinner blade for vibration.
These all add drag to the weight to help pull it down stream. Working with the variables a choice has to be made by the fisherperson. Many times you cant add these as its added drag in the water hurts you even more.
Like in boating when you drop the anchor you may have made a poor choice at that moment. This is a little off topic butt there is a lot going on down in the water, things i got to know about to improve my choices. :-\
Luckily lead can be remelted and cast into many other trial molds. I,m going to try the pyramid or cylinder weight when I can.
Yes the grey background was easy on my eyes, I dont know how you folks can do the endless blues skys? ;D
I enjoy learning stuff, you, all have been good.
Quote from: gstours on August 31, 2020, 08:05:13 PM
Thanks, it seems like a flat bottom will have square edges and resist rolling or tipping more than the round cannonball that is most popular here. We fish sandy, pebbles, mud mostly with bottom foliage.
Some folks have shown me some rectangular lead sinkers usually 2-3 pounds they like more than cannonball weights.
Line diameter, depth, and bait size also comes here into the constant equation.
too lazy to read all 26 replies, so if noone said it...
mini-mushroom-anchor
EDIT THAT: make micromini-mushroom-anchors
...or, get 2 regular mushroom anchors to breed & keep drowning the babies