E
ED (The ORIGINAL and REAL one)
Guest
What do you expect -- these traditionalists live in the past !!
F
Fred Bonney
Guest
Talking of which,Dave,where have you been?
Just show's that this (old) site, still has the stuff to read, that is of interest to newcomers.
I's also good to see that people are prepared to look back, rather than deal with the instant.
Just show's that this (old) site, still has the stuff to read, that is of interest to newcomers.
I's also good to see that people are prepared to look back, rather than deal with the instant.
C
Chris Bishop
Guest
Fred Blake, what an eloquent post. Made my morning reading that, even though I'm a carbon fibre heathen who has no inclination to fish with some old tree branch. Please become a regular.
R
Ron 'The Hat' Clay (ACA-Life Member)
Guest
The truth of the matter is that modern carbon fibre, especially from the stable of Harrisons (they ARE the best in my opinion) is far superior to split cane.
There is perhaps one style of angling were split cane is better and that is short accurate fly fishing.
The vast majority of my rods, both fly and coarse are Harrison, or made up on Harrison blanks.
Why are they better? Well you only have to pick up a Harrison rod and you will feel that hard to define property known as "dampening". They don't wobble or flop.
Much like the properties possessed by split cane in the old days.
There is perhaps one style of angling were split cane is better and that is short accurate fly fishing.
The vast majority of my rods, both fly and coarse are Harrison, or made up on Harrison blanks.
Why are they better? Well you only have to pick up a Harrison rod and you will feel that hard to define property known as "dampening". They don't wobble or flop.
Much like the properties possessed by split cane in the old days.
D
Dave O'L
Guest
I agree Fred (hello again) - I was recently looking up old info on running a fishing club.
As to where I've been? I'd love to ba able to say that I've been fishing but unfortunately I've just been caught up with all the things that I didn't have to do back then.
Mind you I hate to admit it but I was addicted to FM - I was spending hours in front of the screen. I had to go 'cold turkey' - Oh and take FM off my homepage. It was the only way.
Hope all is well.
As to where I've been? I'd love to ba able to say that I've been fishing but unfortunately I've just been caught up with all the things that I didn't have to do back then.
Mind you I hate to admit it but I was addicted to FM - I was spending hours in front of the screen. I had to go 'cold turkey' - Oh and take FM off my homepage. It was the only way.
Hope all is well.
Fred Blake
Well-known member
I'd be interested to know why you think that split cane is better for short, accurate fly casting. I should point out that I happen to agree with you - and I hope the reasons will become clear from what follows.
Of all rod types (apart from long float fishing rods and poles of course)it is the fly rod that has benefitted most from the advent of carbon fibre. The 'dampening' characteristic you mention (a product of the material's stiffness to weight ratio) assists greatly in shooting line; a rod that continues to vibrate at the end of the forward cast increases friction to the passage of the line. This applies equally to all fly rods, long or short. OK, you may not need to shoot line in the sort of close-quarters fishing for which cane rods are often recommended, but that alone does not make the cane rod better - equal, yes. But there is one property of cane that is a definite advantage; significantly, it applies to more than just fly rods.
This is the rod's ability to bend against its own weight (that weight/stiffness ratio again). In fly rods this means that a shorter length of fly line can flex the rod enough for comfortable casting; the same effect can be achieved by using a line one or two sizes heavier on a carbon rod, but this is obviously an unsatisfactory solution as, should a trout rise fifteen yards away, you'll overload the rod trying to reach it. The alternative is to stick with the recommended line size and adopt a faster casting stroke, but this ruins accuracy.
This flexing property of spilt cane has applications in some coarse fishing situations; casting directly from a centrepin (Wallis casting) is one, as the slower action of the rod is more suited to the style. Another is when casting a light bait on freeline tackle. Try a simple experiment: take two rods of equal length and test curve - say 10 foot with 1.5lb tc - one of split cane and one of carbon; the latter will probably have to be a spinning rod of some sort. See how far you can throw a wetted crust with each. My money is on the cane rod every time.
It is the test curve and the taper of a rod which primarily dictates its fish playing abilities - a progressive-actioned rod of 1.5lbs test will behave exactly the same with a 10lb carp on the end of the line regardless of the material used, although cross-sectional shape and density play a part.
The cane rod may feel less powerful, but it isn't - it will actually resist bending better than a hollow tubular rod of any material you care to name.
There is room for both cane and carbon rods in modern fishing; understanding the properties of each and knowing where to use them will assist considerable in one's success - and enjoyment - of the sport.
Cane rods should certainly not be dismissed out of hand.
Of all rod types (apart from long float fishing rods and poles of course)it is the fly rod that has benefitted most from the advent of carbon fibre. The 'dampening' characteristic you mention (a product of the material's stiffness to weight ratio) assists greatly in shooting line; a rod that continues to vibrate at the end of the forward cast increases friction to the passage of the line. This applies equally to all fly rods, long or short. OK, you may not need to shoot line in the sort of close-quarters fishing for which cane rods are often recommended, but that alone does not make the cane rod better - equal, yes. But there is one property of cane that is a definite advantage; significantly, it applies to more than just fly rods.
This is the rod's ability to bend against its own weight (that weight/stiffness ratio again). In fly rods this means that a shorter length of fly line can flex the rod enough for comfortable casting; the same effect can be achieved by using a line one or two sizes heavier on a carbon rod, but this is obviously an unsatisfactory solution as, should a trout rise fifteen yards away, you'll overload the rod trying to reach it. The alternative is to stick with the recommended line size and adopt a faster casting stroke, but this ruins accuracy.
This flexing property of spilt cane has applications in some coarse fishing situations; casting directly from a centrepin (Wallis casting) is one, as the slower action of the rod is more suited to the style. Another is when casting a light bait on freeline tackle. Try a simple experiment: take two rods of equal length and test curve - say 10 foot with 1.5lb tc - one of split cane and one of carbon; the latter will probably have to be a spinning rod of some sort. See how far you can throw a wetted crust with each. My money is on the cane rod every time.
It is the test curve and the taper of a rod which primarily dictates its fish playing abilities - a progressive-actioned rod of 1.5lbs test will behave exactly the same with a 10lb carp on the end of the line regardless of the material used, although cross-sectional shape and density play a part.
The cane rod may feel less powerful, but it isn't - it will actually resist bending better than a hollow tubular rod of any material you care to name.
There is room for both cane and carbon rods in modern fishing; understanding the properties of each and knowing where to use them will assist considerable in one's success - and enjoyment - of the sport.
Cane rods should certainly not be dismissed out of hand.
R
Ron 'The Hat' Clay (ACA-Life Member)
Guest
Well what can I say?
What a superb post Fred, you have answered you own question far better than me.
As you say there is still room for split cane in modern angling.
And I am not a traditionalist at all.
What a superb post Fred, you have answered you own question far better than me.
As you say there is still room for split cane in modern angling.
And I am not a traditionalist at all.
R
Ron 'The Hat' Clay (ACA-Life Member)
Guest
By the way Fred, a hollow tube will have a tendency to change from a circle to an oval in cross section when bent. When this happens it's stiffness becomes less.
This does not happen with split cane.
Split cane has a rather wondrous property in that if you study bamboo, the density of the fibres becomes progressively greater as you reach the outside of the wall of the cane. Think about it.
Where the maximum bending stresses are taking place, ie on the outside of the material, cane is at its strongest.
This gives cane its "steely" feel. The only drawback with cane is its weight.
Bruce and Walker developed Hexagraph carbon for this very reason. The trouble is, it is extremely expensive and too heavy compared with a top class carbon tube.
This does not happen with split cane.
Split cane has a rather wondrous property in that if you study bamboo, the density of the fibres becomes progressively greater as you reach the outside of the wall of the cane. Think about it.
Where the maximum bending stresses are taking place, ie on the outside of the material, cane is at its strongest.
This gives cane its "steely" feel. The only drawback with cane is its weight.
Bruce and Walker developed Hexagraph carbon for this very reason. The trouble is, it is extremely expensive and too heavy compared with a top class carbon tube.
Fred Blake
Well-known member
Thanks Ron - I hesitated to go into detail about the behaviour of tubular rods under deflection for fear of blinding people with science! What you say is perfectly true, although probably not appreciated by the majority of modern anglers. With that in mind I suppose an explanation may be useful to some readers.
In essence, the stiffness of a tube under deflection is the product of the major axis and the cube of the minor axis; as soon as a tube is deflected the axis of deflection decreases and the axis perpendicular to the deflection increases - in other words, there is a tendency for the cross-sectional circle to become an oval. Each axis must alter by the same proportion as the circumference of the tube cannot change.
Now, assuming a change of 10% either way, that becomes 110% x 90% x 90% x 90% which works out at about 80%; in other words the ability of the tube to resist further deflection is now 80% of what it was before any deflection took place.
From this it is clear that any tubular rod becomes weaker the more it is bent; the art of the modern rod designer lies in adjusting the tapers such that this tendency is diguised as much as possible in use - in most cases increasing the rate of taper gives the correct impression of progressive power.
Incidentally, although the properties of deflection in tubular structures has been known by engineers for a very long time, the first person to explain this to the wider angling public was none other than our old friend **** Walker in 'Rod Building For Amateurs'.
In essence, the stiffness of a tube under deflection is the product of the major axis and the cube of the minor axis; as soon as a tube is deflected the axis of deflection decreases and the axis perpendicular to the deflection increases - in other words, there is a tendency for the cross-sectional circle to become an oval. Each axis must alter by the same proportion as the circumference of the tube cannot change.
Now, assuming a change of 10% either way, that becomes 110% x 90% x 90% x 90% which works out at about 80%; in other words the ability of the tube to resist further deflection is now 80% of what it was before any deflection took place.
From this it is clear that any tubular rod becomes weaker the more it is bent; the art of the modern rod designer lies in adjusting the tapers such that this tendency is diguised as much as possible in use - in most cases increasing the rate of taper gives the correct impression of progressive power.
Incidentally, although the properties of deflection in tubular structures has been known by engineers for a very long time, the first person to explain this to the wider angling public was none other than our old friend **** Walker in 'Rod Building For Amateurs'.
R
Ron 'The Hat' Clay (ACA-Life Member)
Guest
The theory that a tube becomes weaker the more it is bent has an effect on its speed of recovery from being bent. When the bent rod is released it gets more powerful as it recovers from bending. Hence tubular rods are probably better for distance casting.
An analogy here can be made to a recurve bow. Which takes more effort relatively to start drawing the bow. When it is released the string effort behind the arrow gets greater - relatively of course.
However a different set of parameters take place when casting a fly line. The only advantage of carbon fibre is that the material is much much lighter. If one could achieve the same characteristics of cane, in a rod as light, if not lighter than carbon, you would have perfection in fly rods.
An analogy here can be made to a recurve bow. Which takes more effort relatively to start drawing the bow. When it is released the string effort behind the arrow gets greater - relatively of course.
However a different set of parameters take place when casting a fly line. The only advantage of carbon fibre is that the material is much much lighter. If one could achieve the same characteristics of cane, in a rod as light, if not lighter than carbon, you would have perfection in fly rods.
T
Tony Rocca
Guest
Smashing posts Fred,
As most of my fishing over the past 20 odd years has been with cane, I only tried some carbon barbel rods for the first time this winter, I can offer my own comparison.
The disadvantages of cane are obvious, it is heavy and cant cast 4oz 60 yrds on the big river, I rarely float fish with cane as it hurts my arm after a while.
The advantage of using cane on the river is that I can usually hold bottom with considerably less lead than my counterparts 1lb 10oz or 2lb test rods due to the soft nod of the top as opposed to the stiff top that moves the lead at the first bit of downstream debris. The modern carbon flood rods are designed with slightly softer tops for this reason. I dont need one, nor does anyone really.
But the real joy comes in the playing of fish on cane. I had a great deal of difficulty when I hooked my firt couple of barbel on my loaned Peregrines this winter. I hadnt got a bloody clue what the fish were doing, where they were off to, or when they were ready for the net. I was used to being able to feel everything the fish were doing and found it very strange not to be able to do so, to a far lesser extent anyway. I got the hang of it in the end but the expeirience is far inferior to playing a fish on cane in my opinion. I just didnt feel in touch.
I also found that the seemingly more powerfull carbon rods didnt speed up the landing of fish, you would be suprised at the power in a cane butt.
So, having tried the dark side its still cane all the way for me, try it, you never know it might just enhance your angling experience.
As most of my fishing over the past 20 odd years has been with cane, I only tried some carbon barbel rods for the first time this winter, I can offer my own comparison.
The disadvantages of cane are obvious, it is heavy and cant cast 4oz 60 yrds on the big river, I rarely float fish with cane as it hurts my arm after a while.
The advantage of using cane on the river is that I can usually hold bottom with considerably less lead than my counterparts 1lb 10oz or 2lb test rods due to the soft nod of the top as opposed to the stiff top that moves the lead at the first bit of downstream debris. The modern carbon flood rods are designed with slightly softer tops for this reason. I dont need one, nor does anyone really.
But the real joy comes in the playing of fish on cane. I had a great deal of difficulty when I hooked my firt couple of barbel on my loaned Peregrines this winter. I hadnt got a bloody clue what the fish were doing, where they were off to, or when they were ready for the net. I was used to being able to feel everything the fish were doing and found it very strange not to be able to do so, to a far lesser extent anyway. I got the hang of it in the end but the expeirience is far inferior to playing a fish on cane in my opinion. I just didnt feel in touch.
I also found that the seemingly more powerfull carbon rods didnt speed up the landing of fish, you would be suprised at the power in a cane butt.
So, having tried the dark side its still cane all the way for me, try it, you never know it might just enhance your angling experience.
Mark Wintle
Well-known member
Ron and Fred,
Many years ago, one or other of Tony Fordham or Derek Davenport (can't remember which only that they were both rod builders) heard all this NONSENSE about tube deflecting (ovality) and put it to some very careful testing. He needed to know so that he could take it into account when designing rods (or not as it turned out). In practical angling use he was unable to measure any such deflection in fishing rods! He was using micrometers to try to find the distortion. He found NONE! Yes, in the lab you might find a tube (a drinking straw?)that will deflect in this way but a fishing rod that did so would be a disaster. This argument cropped up in the early sixties with some of the early, badly designed glass rods yet was unproven then.
I agree with the different casting properties of the different materials; last summer when I fished with a glass match rod (incidently with what was the fastest action of its time) ABU Mk 6 it took me an hour to get used to the slow casting action but once I did it was as effective as a carbon rod though twice as heavy and cumbersome.
Many years ago, one or other of Tony Fordham or Derek Davenport (can't remember which only that they were both rod builders) heard all this NONSENSE about tube deflecting (ovality) and put it to some very careful testing. He needed to know so that he could take it into account when designing rods (or not as it turned out). In practical angling use he was unable to measure any such deflection in fishing rods! He was using micrometers to try to find the distortion. He found NONE! Yes, in the lab you might find a tube (a drinking straw?)that will deflect in this way but a fishing rod that did so would be a disaster. This argument cropped up in the early sixties with some of the early, badly designed glass rods yet was unproven then.
I agree with the different casting properties of the different materials; last summer when I fished with a glass match rod (incidently with what was the fastest action of its time) ABU Mk 6 it took me an hour to get used to the slow casting action but once I did it was as effective as a carbon rod though twice as heavy and cumbersome.
S
Sean Meeghan
Guest
Careful gents you're in danger of trying to compare a qualitative 'feel' with a quantitative engineering problem.
Firstly, I'd be interested to know what the percentage deformation in section of a modern rod is when loaded to, say, its nominal test curve rating. I'd be surprised if it got over 1 or 2 percent. Any more and you'd probably start to get a breakdown in the resin matrix.
Secondly, how can you say that a bamboo rod will resist bending better than a tubular rod made of any material? That in itself is a qualitative staement. You'd need to define the tube taper, diameter, wall thickness and many other parameters as well as the almost impossible task of defining parameters for the bamboo structure. Ron is right in that Bruce and Walker have attempted to go down this track with somewhat questionable results.
Feel in a rod is a very personal thing, but to try and describe and justify your preferences in engineering terms is like debating how many angels can dance on the head of a pin.
Interesting discussion though!
Firstly, I'd be interested to know what the percentage deformation in section of a modern rod is when loaded to, say, its nominal test curve rating. I'd be surprised if it got over 1 or 2 percent. Any more and you'd probably start to get a breakdown in the resin matrix.
Secondly, how can you say that a bamboo rod will resist bending better than a tubular rod made of any material? That in itself is a qualitative staement. You'd need to define the tube taper, diameter, wall thickness and many other parameters as well as the almost impossible task of defining parameters for the bamboo structure. Ron is right in that Bruce and Walker have attempted to go down this track with somewhat questionable results.
Feel in a rod is a very personal thing, but to try and describe and justify your preferences in engineering terms is like debating how many angels can dance on the head of a pin.
Interesting discussion though!
R
Ron 'The Hat' Clay (ACA-Life Member)
Guest
One thing I forgot to point out is to do with the outside diameter of the rod and the effect of air resistance.
If I remember, the air resistance on a section varies as the forth power of it's diameter. That means if you double the diameter of a fishing rod the air resistance increases 16 fold.
Carbon rods have enabled us to cast a great deal easier into a wind because of this.
If I remember, the air resistance on a section varies as the forth power of it's diameter. That means if you double the diameter of a fishing rod the air resistance increases 16 fold.
Carbon rods have enabled us to cast a great deal easier into a wind because of this.
R
Ron 'The Hat' Clay (ACA-Life Member)
Guest
Sean and Mark,
Many years ago **** Walker had a long written arguement with Geoff Bucknall in the letter pages on Trout and Salmon. What happened was that Bucknall advised rod makers to stuff plugs up the bore of glass rods to give increased strength at the stress points. He did not elabrate where those stress points could be.
Walker counted this by stating that there were no such stress points in any tubular glass rod that he knew of. He also said that he had access to extremely accurate measuring devices and that he had noticed no such tendency to ovality when the rods had been bent to nearly fracture point.
In practice this is true.
Please note Mark, my observations are based on pure theory and I am fully aware of what happens in practice. I am perhaps one of those rare people today who have fished with rods made from greenheart, lancewood and spit cane to glassfibre, boron and carbon.
The last thing I would ever use today is a split cane rod for barbel or carp fishing. Certainly not for float fishing either. And the last thing I would ever want is a split cane 10 foot reservoir fly rod similar to Tom Ivens' "Iron Murderer".
However I would certainly use a split cane rod for fly fishing where accuracy is paramount over short distances
Many years ago **** Walker had a long written arguement with Geoff Bucknall in the letter pages on Trout and Salmon. What happened was that Bucknall advised rod makers to stuff plugs up the bore of glass rods to give increased strength at the stress points. He did not elabrate where those stress points could be.
Walker counted this by stating that there were no such stress points in any tubular glass rod that he knew of. He also said that he had access to extremely accurate measuring devices and that he had noticed no such tendency to ovality when the rods had been bent to nearly fracture point.
In practice this is true.
Please note Mark, my observations are based on pure theory and I am fully aware of what happens in practice. I am perhaps one of those rare people today who have fished with rods made from greenheart, lancewood and spit cane to glassfibre, boron and carbon.
The last thing I would ever use today is a split cane rod for barbel or carp fishing. Certainly not for float fishing either. And the last thing I would ever want is a split cane 10 foot reservoir fly rod similar to Tom Ivens' "Iron Murderer".
However I would certainly use a split cane rod for fly fishing where accuracy is paramount over short distances
R
Ron 'The Hat' Clay (ACA-Life Member)
Guest
Sean,
Another point. Greenheart, lancewood, glassfibre and carbon fibre are basically homogenous materials. That means that there is no various in physical properties throughout the thickness of the material, whether that material be formed into a tube, or left solid.
I know there have been many attempts in the past using kevlar fibres to stiffen up, or strengthen carbon fibre tubes, but this has not been too successful. The addition of these wraps has only added weight because they have been put on the blank in a radial or spiral wrap. Not axially.
Split cane is far from homogeneous.
From the inside of the bamboo, the fibres get more and more dense until they reach a peak on the outside skin.
This "asymmetric" structure is what gives cane it's unique properties. This is something that would be extremely difficult and frightfully costly to achieve using synthetic materials.
Another point. Greenheart, lancewood, glassfibre and carbon fibre are basically homogenous materials. That means that there is no various in physical properties throughout the thickness of the material, whether that material be formed into a tube, or left solid.
I know there have been many attempts in the past using kevlar fibres to stiffen up, or strengthen carbon fibre tubes, but this has not been too successful. The addition of these wraps has only added weight because they have been put on the blank in a radial or spiral wrap. Not axially.
Split cane is far from homogeneous.
From the inside of the bamboo, the fibres get more and more dense until they reach a peak on the outside skin.
This "asymmetric" structure is what gives cane it's unique properties. This is something that would be extremely difficult and frightfully costly to achieve using synthetic materials.
Fred Blake
Well-known member
Well, we seem to have stirred things up a bit here! I'll try and respond to the various points in the order that they have been made.
Ron - you are again quite right in suggesting that as a tubular rod recovers from bending, its power is effectively increased. What it certainly does not do is enhance the innate power of the rod. It's the same principle as a variable potentiometer in an electrical circuit, which cuts off some of the current as you turn it - a volume control on a radio for example. The current is still fixed. A rod can only generate the power it is capable of, no more. Bending a tubular rod reduces the power; unbending gives it back.
The bow analogy is irrelevant in this context; the way a longbow reacts under deflection will be subject to exactly the same principles as a fishing rod and is dependant on the material used in the same way. You cannot compare how the bowstring reacts to how a rod does; the rod and the bow are the same, not the string.
Mark - you say that there is no detectable distortion in a tubular fishing rod. In the tip sections no; they will fracture before any measurable change in the shape of the tube. The lower sections do show some distortion - only slightly, but they do all the same. The reason behind this is the relationship between the diameter of the tube and the wall thickness.
This distortion is actually very tiny; Sean suggests that it cannot be more than 1 or 2 percent. In fact it is more like 0.03 of a percent, or about 1 ten-thousandths of an inch in a typical fly rod butt. Insignificant in practical terms certainly; a tiny change in taper is sufficient to nullify any perceived weakness, which is why modern tubular rods are entirely satisfactory.
The fact remains however, that solid rods do not distort; half of the rod's cross section (that which falls above a line drawn through the centre of the rod in such a way as to leave the same area of material on either side) will be under tension, wheras the half below the line will be under compression; both halves want to move towards this line of neutrality but, as the tension and compression are equal, they are not able to, so no distortion occurs.
Sean - you ask how it is that a bamboo rod can resist bending better than a tubular rod? You are right to point out that such a test requires comparable rods, but it does not mean identical tapers, blank diameter or wall thicknesses; for one thing you don't have a wall thickness in a solid split cane rod. What you can do however is produce a cane blank and a tubular blank with the same curve under load i.e. the same test curve in pounds and the same rate of curvature. The blanks themselves will appear quite different but this doesn't matter - we are not comparing blank diameter or taper here. Having done this, put them under load. There will be no appreciable difference until, with carbon fibre anyway, the tubular rod breaks; this will happen before the cane one does.
Beyond a certain point the tubular rod begins to distort but, due to the bittleness of the material, fracture occurs before the distortion becomes so much that the rod's resistance to deflection becomes noticeable. To stop the tube fracturing it would be necessary to make it out of a less brittle material such as mild steel, which would make the decrease in resistance due to ovality of the cross section quite noticeable - but this would result in a heavy floppy rod quite useless for fishing. The principle however is the same.
The solid rod will keep going on resisting until the fibres on the outside of the curve seperate by being pulled apart; what governs this is tensile strength of the longitudinal fibres and good quality bamboo has plenty of it.
To be continued...
Ron - you are again quite right in suggesting that as a tubular rod recovers from bending, its power is effectively increased. What it certainly does not do is enhance the innate power of the rod. It's the same principle as a variable potentiometer in an electrical circuit, which cuts off some of the current as you turn it - a volume control on a radio for example. The current is still fixed. A rod can only generate the power it is capable of, no more. Bending a tubular rod reduces the power; unbending gives it back.
The bow analogy is irrelevant in this context; the way a longbow reacts under deflection will be subject to exactly the same principles as a fishing rod and is dependant on the material used in the same way. You cannot compare how the bowstring reacts to how a rod does; the rod and the bow are the same, not the string.
Mark - you say that there is no detectable distortion in a tubular fishing rod. In the tip sections no; they will fracture before any measurable change in the shape of the tube. The lower sections do show some distortion - only slightly, but they do all the same. The reason behind this is the relationship between the diameter of the tube and the wall thickness.
This distortion is actually very tiny; Sean suggests that it cannot be more than 1 or 2 percent. In fact it is more like 0.03 of a percent, or about 1 ten-thousandths of an inch in a typical fly rod butt. Insignificant in practical terms certainly; a tiny change in taper is sufficient to nullify any perceived weakness, which is why modern tubular rods are entirely satisfactory.
The fact remains however, that solid rods do not distort; half of the rod's cross section (that which falls above a line drawn through the centre of the rod in such a way as to leave the same area of material on either side) will be under tension, wheras the half below the line will be under compression; both halves want to move towards this line of neutrality but, as the tension and compression are equal, they are not able to, so no distortion occurs.
Sean - you ask how it is that a bamboo rod can resist bending better than a tubular rod? You are right to point out that such a test requires comparable rods, but it does not mean identical tapers, blank diameter or wall thicknesses; for one thing you don't have a wall thickness in a solid split cane rod. What you can do however is produce a cane blank and a tubular blank with the same curve under load i.e. the same test curve in pounds and the same rate of curvature. The blanks themselves will appear quite different but this doesn't matter - we are not comparing blank diameter or taper here. Having done this, put them under load. There will be no appreciable difference until, with carbon fibre anyway, the tubular rod breaks; this will happen before the cane one does.
Beyond a certain point the tubular rod begins to distort but, due to the bittleness of the material, fracture occurs before the distortion becomes so much that the rod's resistance to deflection becomes noticeable. To stop the tube fracturing it would be necessary to make it out of a less brittle material such as mild steel, which would make the decrease in resistance due to ovality of the cross section quite noticeable - but this would result in a heavy floppy rod quite useless for fishing. The principle however is the same.
The solid rod will keep going on resisting until the fibres on the outside of the curve seperate by being pulled apart; what governs this is tensile strength of the longitudinal fibres and good quality bamboo has plenty of it.
To be continued...
Fred Blake
Well-known member
I am not attempting to justify my preferences in engineering terms; you will see from my earlier posts I use carbon, glass and cane rods, my choice for any particular situation being based on an understanding of the principles involved allied to what can only be termed 'feel'. I agree that you should not rely solely on science in designing or selecting suitable fishing tackle, but I do think it is beneficial to understand the physics of rod behaviour - if only as a matter of interest.
There is one other aspect of rod design which, so far, we haven't touched upon - striking efficiency or, more to the point, hooking power. All other things being equal, the heavier rod will strike a hook home better than a light one, especially if the weight is towards the tip.
Consider what happens when you knock a nail into a piece of wood. A hammer is just a very short, stiff rod, with a weight at the end. That weight determines how much of the force you apply is transmitted to the head of the nail. Try it. Knock a nail in. Then take the head of the hammer off. You are still holding a short rod, except now it is much lighter - and very slightly stiffer due to the reduced weight. Try to knock another nail in. You'll find you have to hit it much harder. Put the head back on, but this time hold the hammer the other way around and try to drive a nail in; this time, although the rod is still the same length, its weight is back to what it was the first time. Why then does it still require more effort to hammer the nail right in? The answer lies in the weight distribution.
Now I know a heavier rod is a slower rod, so whilst you gain in power you lose in speed. I don't believe that one cancels the other out; in rods up to about 12 feet I do think there is some advantage in certain circumstances having this extra weight, particularly where large hooks are in use. The opposite is true when fishing with very light lines; it is here that carbon fibre rods shine, as it is possible to reduce the shock of the strike without sacrificing tip speed.
There is one other aspect of rod design which, so far, we haven't touched upon - striking efficiency or, more to the point, hooking power. All other things being equal, the heavier rod will strike a hook home better than a light one, especially if the weight is towards the tip.
Consider what happens when you knock a nail into a piece of wood. A hammer is just a very short, stiff rod, with a weight at the end. That weight determines how much of the force you apply is transmitted to the head of the nail. Try it. Knock a nail in. Then take the head of the hammer off. You are still holding a short rod, except now it is much lighter - and very slightly stiffer due to the reduced weight. Try to knock another nail in. You'll find you have to hit it much harder. Put the head back on, but this time hold the hammer the other way around and try to drive a nail in; this time, although the rod is still the same length, its weight is back to what it was the first time. Why then does it still require more effort to hammer the nail right in? The answer lies in the weight distribution.
Now I know a heavier rod is a slower rod, so whilst you gain in power you lose in speed. I don't believe that one cancels the other out; in rods up to about 12 feet I do think there is some advantage in certain circumstances having this extra weight, particularly where large hooks are in use. The opposite is true when fishing with very light lines; it is here that carbon fibre rods shine, as it is possible to reduce the shock of the strike without sacrificing tip speed.
R
Ron 'The Hat' Clay (ACA-Life Member)
Guest
One of the problems with carbon rods, especially rods used for fly fishing is the way they are made.
The carbon fibre pre-preg (cloth so called because it has not yet been soaked in resin) is wrapped around a steel mandril. Rolled up if you like like a toilet roll.
This means that axially, a strip of the blank will be slightly thicker caused by the overlap. This causes what is known as a "spine" in the blank. This results in what is termed a "preferred plane of bending"
You can easily spot this on any carbon rod. Pick ip up, bend it, then roll the blank in your fingers.
I think that this flaw in carbon blanks can affect accuracy in casting. Something you do not get with good split cane.
The carbon fibre pre-preg (cloth so called because it has not yet been soaked in resin) is wrapped around a steel mandril. Rolled up if you like like a toilet roll.
This means that axially, a strip of the blank will be slightly thicker caused by the overlap. This causes what is known as a "spine" in the blank. This results in what is termed a "preferred plane of bending"
You can easily spot this on any carbon rod. Pick ip up, bend it, then roll the blank in your fingers.
I think that this flaw in carbon blanks can affect accuracy in casting. Something you do not get with good split cane.
Alan Tyler
Well-known member
The "hammer-head" principle led a couple of chaps, unhappy about the striking power of their new-fangled hollow glass rods (1968-ish?), to experiment with a slug of mercury inside the blank, holding the rod tip-down as they trotted so the mercury would pool in the tip and increase the striking power. Once the toxic hazards of mercury had been explained, the idea died, but it was an imaginative bit of thinking!