The Mathematics of Clipping Up

I've just been reading an article written by someone who claims to regularly spod at 120 yards and he was saying that when he clips up and casts his rigs he aims to overshoot the marker by 1ft for every 2ft of water depth to allow for the swinging in motion of the lead. He has come to this conclusion due to "lots of trial and error".
After getting my compass and ruler out I have calculated that at 60yards and in 15feet of water a lead would still only swing roughly 1 1/2feet, now this would obviously be even less at extreme distance due to the radius of the circle being bigger, or in shallower water and is all assuming that the line has no slack or stretch whatsoever in it upon hitting the clip and then the water surface.
Now this got me thinking a bit and has raised these questions:
1)How the hell does he know how far his rig has swung in? He may be using a boat and fishing very clear water I suppose and if so why doesn't he just row his baits out?!
2)Unless you can cast with absolutely no slack at all shouldn't the lead fall vertically through the water untill all the slack has been taken up?
3)Is it drag/resistance on the line falling through the water that causes the pendulum motion rather than distance (if indeed this pendulum motion exists)?
4)Is this just another carp myth that has been theorised by one person and then taken as fact and propagated by others?
5)Is accuracy less important than we are lead to believe aspeople are fishing less accurately than they think they are?
6)Have I got waaaaay to much time on my hands?
I've read about Bob Nudd doing the same and I'll be the first to admit that these guys could outfish me with their eyes closed and one hand stapled to their left knacker, they have an innate ability to understand the behaviour of their quarry that I can only dream of and technique that I can only fantasise about having. But unless I've missed the point somewhere shouldn't they stick to doing what they do best (catching fish) rather than using their slightly shaky grasp of geometry to come up with these over complicated theories?
I hope someone can prove me wrong and explain what does actually happen at the end of the line.

Have you allowed for him being in a standing position with the rod in an upright position for the cast, could give you another 15ft depth.

complete bollox mate

basic maths isn't it?

Pythagoras theorem or builders know it as 3x4x5

The distance through the water to where the lead lands (the hypotenuse) is the square root of the distance cast (side a), squared and the depth of water squared.(side b)

120 yds is 360 feet, at that distance the supposed 'arc' is minimal to say the least.

At 4 feet deep it's a quarter of an inch.
You get an inch arc at 8 feet of depth.

It doesn't swing back over 12 inches until you start hitting 28 feet of water.

I think your numbers may be wrong as well, because at 60 yds and 16 feet deep, I've worked it out as 8.5 inches.

Agree? Disagree?

The maths doesn't work.....

Yeah I allowed the total height of man and rod to equal 5 units (yards) and assumed the rod would be in a perfectly vertical and stayed that way when the line hit they clip as this would simulate a worst case scenario.
That's why I made the depth 15ft, because it made the working out easier having 5 yards above the water line and 5 yards below.

180 (60 yds) squared = 32400
16 (depth) squared = 256
summed = 32656
square root = 180.709712

difference over 180 feet is an extra 0.7 feet or about 8.5 inches.

....he got there before me. Totally agree with Rik. Crap maths.

I was doing it using some ropey scale drawings just to give me a rough guide Rik but I would certainly agree with your workings out and that's not taking into account that you can't cast and land it on the surface of the water on a perfectly tight line and you don't cast with your rod ending in a perfectly vertical position.

Pythagoras' theorem only works for a right angled triangle, but if you assume thats the case then its a fair approximation.

I think it was Tony Miles who done an article on this somewhere, and the distances due to the lead swinging in an arc inwards are minimal.

PS - I was having a go a the original post Bynasty in terms of the article you read and the persons assumption of overshooting by 1ft for every 2ft of depth......which is absolute crap !!

don't read crappy carper.you won't get tied up in knots

That's alright Bully, I took it as that.
Eddie, I did contemplate doing some proper calculating but my memory when it comes to formula's for tangents and the like stopped working when I stopped doing physics at uni! The scale drawing gave me enough of a guide to roughly disprove it.
Was it Coarse Angling today cos now you mention it it sounds vaguely familiar?

I think the original article was by a chap called Keith??? in one of Tim Paisley's books and I think it was Tony Miles that shot it to pieces.

Nope, it was Jim Gibbinson that shreds the idea in Gravel Pit Carping.

whatever, so wot does all this mean to me, Rik will tell ya and Bully is yet to find out I am totally number dislexic, please explain.

if im casting my bait 100 yards and it hits the water at 100 yards what distance does it land and where do i spod my bait?

I'm serious about the number thing btw.

You read it too then William? It just made me laugh that the guy didn't even quantifying it by saying at range X you would have to overshoot by Y ammount for a depth of Z, he just made a ridiculous sweeping statement.
I don't want to offend anyone on here but most of the carp fishermen or indeed any angler I meet are quite often not the sharpest tools in the box (this forum seems to be the exception) although they are still far better anglers than myself, but these guys write articles that treat fishing as if it's an exact science that they all have Phd's in. It makes me laugh because you then hear the next guy regurgitate the same crap as if it's a set in stone fact.

bollox, wheres me bait boat!

Stick to wonder rigs Stu and just know that it's there or there abouts!

Stik two ure beat baits Stew, weee well hulp u wif thur wrest.

must admit though m8 crappy carper was better before martin ford took over.but,if you are spodding at 100 plus yards with mono a fully laden spod(apparently korda skyliners are his fave)weighing around 7 ounces will need a forcefull punch to hit the target surely the amount of bounce/stretch will affect the casting and the precise hitting of the target area