Death Rigs

[jason fisher]

bullshit spoken on the mathematical side but I'll not go into that now. It's very difficult to apply mathematic concepts to a set of conditions so variable.

ron it may be a gross oversimplification of a quite complex modelling problem but the principle still stands.

if you are attempting to imply that the smaller the fish the greater the velocity required for it to break the line is wrong then you are wrong.

 

[Ron 'The Hat' Clay]

Of course F=MA.

Simple fact of physics.

But try modelling the number of variables into somthing that can be calculated in this instance.

It blows my mind.

Personally it would be easier to apply some basic common sense.

 

[jason fisher]

you could model it but it would be a right sod to do.

that's why i simplified it to that degree, it's not bullshit just simplified to illustrate a point and so is under the terms of the simplification correct, not bullshit as you suggested.

 

[Bob Roberts]

Glad you lot know what you're talking about. In fact I'm so relieved you've simplified it or I wouldn't have a clue what you were on about.

Come to think of it I still haven't.

Simple question. If I try to lift a 6lb fish with 4lb line above the water, the line would break. If I do the same exercise under water it won't. Therefore, assuming a feeder becomes snagged whilst playing a fish, thus stopping that fish in its tracks, can it, from a standing start with an 18 inch hook link, break 4lb line.

Conversely, is thee any way a 4lb fish could break 6lb line in this scenario?

 

[jason fisher]

in your first case then yes it should be able to because the acceleration required would be less than 10ms-2.

for the second case assuming that the feeder is stuck solid and can't move, there is no stretch in the line, the feeder cannot deform, and knots don't weaken the line.

then a 4lb fish would have to accelerate at roughly 15ms-2 to break the 6lb line from a standing start.

this is probably possible, as andy quoted carp can accelerate at 20ms-2.

interestingly rocks actually help the fish escape because they are solid and won't deform a branch on the other hand will most likely bend and make it harder for the fish to escape.

personally i only use running or semi fixed setups because i considered all the factors and decided 2lb roach were worth saving.

 

[jason fisher]

it comes down to the design of the rig, if it works correctly can it tether?

if the answer is yes i don't use it.

everyone knows running rigs can tangle but they aren't designed not to lose the weight they only don't lose the weight if they malfunction.

 

[Ron 'The Hat' Clay]

Again Bob an enormous amount of variables.

If it was travelling fast enough from a standing start it could indeed break the line. It would also depend on the power of the fish. I guess a barbel would have a better chance of breaking the line than a bream of the same weight.

Again we come up against the elasticity of the line. A line with no stretch at 4lbs BS will be more easily broken than a line with some stretch in it. That's why we can play a fish successfully on light tackle using the combined elasticity of the line and the flexibilty of the rod.

Or in the case of a pole, a length of elastic.

Remember one thing. Under water a fish weighs virtually nothing. It only weighs 6lbs say when you lift it from the water.

Imperial measurements are very misleading in terms of calculating things.

Metric is far easier. Force in terms of the metric system is not measured in Kilogrammes, it is measured in Newtons. A Newton is the amount of force required to give an acceleration of 1 metre/sec2 on a mass of 1 kilogramme.

Therefore the BS of lines in the Metric system should be given in Newtons, not Kilogrammes which is a unit of mass, not a unit of force.

 

[jason fisher]

breaking strain on lines shouldn't be given in pounds any way should it?

surely a pound is a mass not a force, isn't it?

i really don't know the answer to this as i grew up metric.

i just presumed they'd taken the force out of the equation to simlpify it for people.

for example you don't buy 10 newton breaking strain line in france it's 1kg, they've just simplified it.

this is incidentally where Andy got things completely wrong in his you're not trying to defeat gravity argument earlier in the thread.

 

[Ron 'The Hat' Clay]

I guess it would make things very complicated for many if they suddenly started selling lines in Newtons BS even though this is correct in terms of the SI.

 

[jason fisher]

you didn't answer the question in my first 2 lines.

 

[Wolfman Woody]

Just read those last few postings and what a load of ..................

What does a 6lb fish weigh in the water? "Sod all!" is the answer because it has neutral boyancy. A fish in the water can only exert a pulling power and with nothing but a fluid to use a leverage that poundage pulled would not be much. albeit, some larger fish do manage quite a pull particularly when they use the current to their advantage. That's not mathematics as I don't believe in wasting paper on something so damned obvious.

If I get it correctly I beleive I am more with Ron on this. There's too many variables, nothing is fixed because it depends on the quality of the line, has it been damaged at all, how well are the knots tied, How old is the line and has it oxidised. Oh boy you do really want toi make a meal of this one.

And "it comes down to the design of the rig, if it works correctly can it tether? if the answer is yes i don't use it." So - Jason, you never use floats with split shot weights fixed to the line then in case the line should break at or above the float rendering it a "tether rig"?

 

[Ron 'The Hat' Clay]

Jason I've forgotten the old imperial terms.

A pound on terms of a force was called a pound force or poundf - I think.

Then there was a thing called a poundal. I've forgotten what that meant. Could have been the force require to make 1 lb mass accelerate at a one foot per sec2

In my work I am 100% metric orientated. except when dealing with the Americans where I have to convert everything to metric and then everything back to imperial when answering them.

 

[jason fisher]

I have stated the accelerations required by fish of given masses to equal the force required to break lines of given breaking strains nothing more.

ron has correctly stated that there are many other factors to consider, however jeff unless you are suggesting that we deliberately use old degraded line to lessen the chances of fish death your argument does not stand.

What does a 6lb fish weigh in the water? "Sod all!" is the answer because it has neutral boyancy.it still has a mass of 6lb and it just happens that the down force due to mass is balanced by the up force due to the water. this force does not magically disappear. it is just counteracted by an equal and opposite force so the net result is zero.

A fish in the water can only exert a pulling power and with nothing but a fluid to use a leverage that poundage pulled would not be much.
To accelerate at 1ms-2 it would have to displace the mass of the fish.

particularly when they use the current to their advantage. certainly jeff,as you know we can always rely on a fish to bolt directly down stream.

So - Jason, you never use floats with split shot weights fixed to the line then in case the line should break at or above the float rendering it a "tether rig"?

floats tend to be a couple of grammes and unless i'm very mistaken have much less probability of becoming immovably trapped in sub surface features. plus i think you will find it doesn't usually take much force to dislodge even a swan shot from a line so they would come under the heading of semi fixed really.
possibly you could put a couple of shot on a line pass the line through a sieve and hang increasing weights on the end i did when i investigated this for my self.

as they say jeff a little knowledge can be dangerous, i would say that as far as Physics is concerned a little knowledge is a very dangerous thing especially when large parts of that knowledge are justified with misconceptions and misunderstandings.

 

[Ron 'The Hat' Clay]

Jeff,

When laying on in a river or using the lift method I often pinch a load of shot about 25 mm (sorry 1 inch) from my hook.

On the hooklength.

Am I being a bad boy?

 

[Ron 'The Hat' Clay]

And by the way Jason, when is your industry going to stop using those truly ghastly and horrendously carcinogenic chemicals that most other semi-conductor plants also use. I read an article recently where it said in some instances such shite is not required anymore.

For several years I used to sell filter cartridges and capsules that cost over ?3k in some cases made from 100% fluorocarbon.

I reckon these things put up the cost of chip manufacture by a considerable amount.

 

[jason fisher]

cheers ron for that bit on imperial.

 

[jason fisher]

"And by the way Jason, when is your industry going to stop using those truly ghastly and horrendously carcinogenic chemicals that most other semi-conductor plants also use. I read an article recently where it said in some instances such shite is not required anymore."


when theyre not we do tend to use the less dangerous things but they usually turn out to be just as bad given a couple of years.

let's face it there's only so many things you can use as a resist medium and none of them are nice, they all give you cancer just some more readily than others, the thing to do is minimise the chance of exposure.

3K's nowt if the machine (tool) costs 2 million.

we change the air about 5 times per hour all the machines are kept in laminar flow and for a lot of the bad stuff the machine had an air lock which only the wafers go through which is purged to scrubbers for example, the other advantage of this is you don't expose the wafers to people, people are one of the greatest harards to the survivability of a semiconductr device.

 

[Ron 'The Hat' Clay]

I often wonder what the environmental effects are on the disposal of such toxic cocktails.

I sold a large set of special carbon cartridges to an electronics plant in Germany who wanted to dispose of a batch of contaminated water into a canal a few years ago. The filters worked but then they were incinerated.......

Someone somewhere must have breathed some of the fumes.

Still we all use computers these days which are full of semi-conductors and electronics manufacturing is the world's second largest industry I believe.

 

[jason fisher]

dresden was it.

 

[Wolfman Woody]

" plus i think you will find it doesn't usually take much force to dislodge even a swan shot"

I think you'll find if they've been fixed properly to withstand heavy casting it's more than a small roach or dace could pull off - and - YES they can get caught in underwater features like submerged branches. I think you make the rules to suit yourself Jason! Like I said before, show me any fishing rig that is 100% safe.

It hasn't been offered yet. Claim the title.