Line strength capacity of a rod

When a particular rod is described as taking line up to 8lb. how is this decided? What does it mean if the 8lb. line is exceeded?

From an engineering/material strength point of view, if you exceed the recommended line rating significantly then you risk breaking the rod if sufficient load is applied. ie if a rod has a recommended rating of 8lb then under a normal steady load the line will break before the rod. it doesn't mean you cant use 10lb, but you reduce that factor of safety.

I think the ratings given are to give us an idea of the style of fishing that the rod is designed / suitable for.

Rarely are rods marked with the load pressures that they are capable of exerting, over which they would fail (break). I think a lot of anglers would be surprised at how low some the actual ratings are.

Mr Cholmondeley-Corker (PaSC) said:

From an engineering/material strength point of view, if you exceed the recommended line rating significantly then you risk breaking the rod if sufficient load is applied. ie if a rod has a recommended rating of 8lb then under a normal steady load the line will break before the rod. it doesn't mean you cant use 10lb, but you reduce that factor of safety.

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Hi Corky,
There used to be a guideline that Line Rating is between 1x and 3x Test Curve.
and
3x Safe Working Load = capacity.
Do the Line rating, Test Curve and SWL have any relationship from an engineering point of view?
Cheers

Yes, the rule of thumb is test curve x 5 for an ideal line breaking strain.

with x 4 being a minimum and x 6 being the maximum

so, for my Greys barbel rod 1.75lb test curve the ideal line bs is 1.75 x 5 = 8.75 (say 8 to 9)

however, you could safely go down to 1.75 x 4 = 7

and up to 1.75 x 6 = 10.5

Having said all that I sue mine with 12lb and have used 15lb on a snaggy river!

Also, I have a heavy feeder (Greys TX) rod that recommends mainline 8 to 12lb and hook lengths down to 2lb.

So, its a rule of thumb that can be used when the manufacture does not state recommended ratings (which I would hope come from calcs based on the mechanics of the blank).

I've long held the view that most rod ratings are fairly arbitrary and based on the rod's intended use rather than any real world measurements. Chuck in the fact that many lines are also rather arbitrarily rated and it's a recipe for disaster. Fortunately, it doesn't really work that way. Many rods, that are actually given line ratings, are way under rated. Should you choose to, you can often get away with way more than a manufacturer states. It's the other side of the coin which sees some manufacturers fail to give line ratings. Both are exercises in backside covering in an attempt to fend off complaints when something breaks.

However, I would tend to follow any guidelines given, give or take the odd pound, based purely on the intended use of the rod. Despite that, I know full well, from experience, that if you are careful, sensible use of drag and backwinding can see you use line way heavier than anything sensible might suggest. I've never boken a rod under load yet, though there's an element of luck to that, but there's a good dollop of common sense too.

More often than not, rods break due to flaws or unnoticed damage. Pulling for breaks with a rod under load is one of the biggest rod breakers I've encountered, usually by inexperienced anglers (or the stupid). One thing I definitely won't do is exceed the reasonable casting weights for a given type of rod, that's asking for trouble compared to putting line a pound or two heavier than suggested upper limits. This is probably the second biggest rod breaker I've seen. People either pushing the weight they are trying to cast or straining for extra distance.

And at the other extreme, using say 4Ib line or hook length with a 1.75Ib TC rod risks breaking the line if a fish lunges sharply or you strike too hard.

Thanks for the replies. Another thing I've learned. I think correct setting of the drag for the rod in question is the way to go.

I tend to take the Manufacturers claims with a pinch of salt. For example I'm currently using a rod which is sold as a 'Barbel' rod, I've had number of chub on it up to 5+, most of which have managed to bend it almost double. I really wouldn't fancy my chances if a decent Boris came along.

I was once on a coaching day with Tommy Pickering and Roy Marlow at the Glebe fishery. Tommy was pulling on his rod rigged with 6lb line, Roy at the other end had a pair of scales hooked in a loop on the end of the line. With a 'hefty' bend in the rod - the scales only read 6 ounces or so. Others then tried it and none managed to get a reading over 1lb. It really makes you think about the exact pressure you may be exerting on a fish whilst it is in the water.

Terry D said:

I was once on a coaching day with Tommy Pickering and Roy Marlow at the Glebe fishery. Tommy was pulling on his rod rigged with 6lb line, Roy at the other end had a pair of scales hooked in a loop on the end of the line. With a 'hefty' bend in the rod - the scales only read 6 ounces or so. Others then tried it and none managed to get a reading over 1lb. It really makes you think about the exact pressure you may be exerting on a fish whilst it is in the water.

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With the stretchiness in nylon monolament lines it makes you wonder what effect switching to braid has on the rod perormance - comments?

I give a passing glance to the line rating for all rods I use but that's as far as it goes. It's a much used term is 'balanced tackle' but for me this is what it comes down to, that and the terms learned from long experience, 'feel' and 'conditions in front of you'......

I invariably try to use the lightest line possible, BUT I only take note of how I'm going to land the fish, once hooked, from the swim in front of me and is my tackle up to the job. Time and time again I have folk come up to me with tales of lost fish and then tell me they fished 4lb line form a swim that needed 8lb at least. NOT to say 4lb might not have worked in different hands, but generally speaking rod/line must be up to the task in the first place - even with the best bait in the world on the other end !!

For me its all about experience learned over time; to be able to adjust the tackle to suit the conditions and change rods/line as necessary. If I lose a fish in a swim I have to consider if the gear was up to the job, or if I was just unlucky with snags or whatever. If it's the former then I don't go back with the same gear next time !!

Yes, have a look at recommended line strengths found on most rods, but it is only a guide and not written in stone......................Using a bit of 'common' is what it's all about in the long run !!!

When a fish is in the water it has neutral buoyancy, that is why it doesn't sink.
If a rod is bent into a curve the effect on the fish is to unbalance it, the fish then tries to correct its balance by swimming forward.
If the line is running off one side of the fish it will have the effect of making the fish use its muscles on one side more than the other and it will weaken sooner.
The simple act of keeping the bend in the rod will tire any fish providing the tackle is balanced.

High sticking, bending the rod into a fish at your feet and lifting the butt to vertical, will break almost any rod, I've seen a 100lb Penn Tuna Stick break when the angler did exactly this.

To set the reel drag, bend the rod into its fighting curve (butt around 45degrees to horizontal) then back off the drag until it gives line comfortably.

Beware that most reel drags straight out of the box need running in by pulling line off against the drag until they run smooth and startup without snatching.

Hope this helps.

Terry D said:

I was once on a coaching day with Tommy Pickering and Roy Marlow at the Glebe fishery. Tommy was pulling on his rod rigged with 6lb line, Roy at the other end had a pair of scales hooked in a loop on the end of the line. With a 'hefty' bend in the rod - the scales only read 6 ounces or so. Others then tried it and none managed to get a reading over 1lb. It really makes you think about the exact pressure you may be exerting on a fish whilst it is in the water.

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Yep, I can totally see this. Anyone who has ever had a custom rod built by Kev Baynes of the Anglers Workshop will be familiar with his demonstrations of rod blanks with a spring balance attached to the tip by a short length of braid. I've seen top-of-the-range proprietry 3lb TC carp rods "bottoming out" at under 10lbs of load, yet his Harrison 'specialist' float rod blanks exert 17lbs of pressure and still have more in reserve.

I agree with mick b, reel drag is most important than line strength when playing fish. I use soft rods and light drag, and get away with much lighter line than most anglers would use

It is only when stuck into a snag that most anglers have any real idea of just how much force can be applied to that rod and line. Very few get anywhere near it whilst playing a fish. The physics of leverage make it quite difficult in any case, unless the rod is getting nearer to pointing directly at the fish.

jayzs said:

... how much force can be applied to that rod and line. .... The physics of leverage make it quite difficult in any case, unless the rod is getting nearer to pointing directly at the fish.

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If the rod is nearly pointing at the fish there is little leverage being applied - unless it's bent double!

Terry D said:

I was once on a coaching day with Tommy Pickering and Roy Marlow at the Glebe fishery. Tommy was pulling on his rod rigged with 6lb line, Roy at the other end had a pair of scales hooked in a loop on the end of the line. With a 'hefty' bend in the rod - the scales only read 6 ounces or so. Others then tried it and none managed to get a reading over 1lb. It really makes you think about the exact pressure you may be exerting on a fish whilst it is in the water.

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Reminds me of when I used go boat fishing off the Yorkshire coast with some lads from work. They all had 30lb - 50lb class rods and equivalent line just as I had used in previous years. I'd moved onto a 12lb class rod and the new-fangled Spiderwire super braid and was using 6oz leads instead of the more normal 16oz - 20oz needed to hold bottom with the heavy outfits. Bear in mind the average size of our quarry was about 3lb and if the whiting were in it was a third of that. Of course I was ribbed mercilessly about my 'kid's pier outfit' so one day I bet Big Pete a fiver that he couldn't lift a gallon bucket of water weighing 10lb from the ground onto a chair using his 50lb Milbro Commander rod. He's 6' 4" and was around 22 stone and despite all the sweat and swearing he couldn't do more than skim the bucket over the ground. His biceps were shaking and sweat poured from his brow, but he couldn't lift the bucket.

It's all about the leverage required and the rod's action. Paradoxically the stiffer action the rod, the less pressure you can exert foot for foot of the rod length as a softer action rod folds more and thus creates a smaller lever.

james said:

Yep, I can totally see this. Anyone who has ever had a custom rod built by Kev Baynes of the Anglers Workshop will be familiar with his demonstrations of rod blanks with a spring balance attached to the tip by a short length of braid. I've seen top-of-the-range proprietry 3lb TC carp rods "bottoming out" at under 10lbs of load, yet his Harrison 'specialist' float rod blanks exert 17lbs of pressure and still have more in reserve.

I agree with mick b, reel drag is most important than line strength when playing fish. I use soft rods and light drag, and get away with much lighter line than most anglers would use

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Blimey...17lb's of pressure with a float rod ! I'm not saying anyone's telling porkies but i'm a little sceptical of that.

Phil Hatton 2 said:

I tend to take the Manufacturers claims with a pinch of salt. For example I'm currently using a rod which is sold as a 'Barbel' rod, I've had number of chub on it up to 5+, most of which have managed to bend it almost double. I really wouldn't fancy my chances if a decent Boris came along.

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Unless its one of those D.A.M. Nano flex rods your prob best during a lunge, being smart with the clutch of the real also (assuming your not using a centre pin) keeping the rod handle somewhere in between vertical and horizontal, like jayz said if its horizontal (pointing at the fish) all the leverage is on the line putting most of the stress/pull on it, if completely vertical the leverage is helped by the rods action but if the reel is locked the stress is all on the rod initially.

Mr Cholmondeley-Corker (PaSC) said:

From an engineering/material strength point of view, if you exceed the recommended line rating significantly then you risk breaking the rod if sufficient load is applied. ie if a rod has a recommended rating of 8lb then under a normal steady load the line will break before the rod. it doesn't mean you cant use 10lb, but you reduce that factor of safety.

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True, but it doesn't mean you cannot break it using 8lb line or less either. It takes an awful of of stress to break 8lb through a rod.