Football: First-down chains

Factual Questions
1

As an avid football fan, I’m embarrased to ask a question like this. But consulting NCAA and NFL rulebooks and hasn’t helped, and perhaps I only think to ask such a question because I love football so much.

What’s the deal with the chains? I understand that they’re to measure for a first down, or more officially, to measure the location of the line to gain. But what I don’t get is how they can be expected to accurately measure the line, and if they can do that, why they even need the chains in the first place. I’ll explain below:

The problem I have with this comes from the fact that the chain gang has to run out to the middle of the field, from the sidelines where they’re stationed, to do the measurements. How can they be sure that they’re putting the back stake right on the original line of scrimmage? You run 20 yards onto a field that is marked in 1-yard increments, and are expected to plant a stake within fractions of an inch of its original location on the sideline. Accuracy to within fraction of an inch is necessary because you’re usually trying to measure a few inches at most.

And if they’re so sure they can get the back stick perfectly placed, why don’t they just do that with the front stick, and forget about needing the chain on the field altogether? The front stake’s location on the sideline is correct, because the length of the chain dictates it. So you shouldn’t need it on the field, as well. And if they can line up the sticks so easily, it would seem that running out on the field is unnecessary, because they know where the sticks are going to end up.

I thought that maybe it has to do with not trusting the field markings. But that’s just not good enough. It still doesn’t explain why they plant the back stick first, and extend the chain, when it’s just as easy to do the same with the front.

Also, I don’t know how they ensure that they’re measuring perpendicular to the line of scrimmage. When you’re talking a couple of inches over ten yards, a small deviation in angle could easily mean the difference between first down and punt.

So, any current or former officials out there? Care to shed any light on this?

2

Ref grabs link on chain corresponding to an exact spot on hash mark or 10 yard increment, then chain is brough onto field and repositioned exaclty as possible on corresponding line.

3

If you watch closely during a measurement, an official carefully marks a major yard line on the chain before they run onto the field. This official keeps his hand on the chain at place he marked it, so when they get out on the field he can reset the chain “middle” to the yard line. They are really marking the measurement by the officials “middle” marker and stretching the front and back poles accordingly.

4

Ahh…that makes a whole lot of sense. I guess the ten yard chain is guaranteed to go over at least one 5-yard line, and usually two.

But the perpendicular question still concerns me.

I’m reminded of the new Budweiser commercial, where the ref says, “Spotting the ball is sort of an inexact science.”

5

As for perpedicularity… a trained eye can easily get to within a fraction of a degree with a quick observation.

One degree off of perpendicular will be accurate to within .015%, or 0.05 inches… about the thickness of a business card.

360 in * (1 - cos(1°)) = 0.0548 in

I think that’s good enough for the NFL. :smiley:

6

The Budweiser advertisement is basically correct.

I think they use the chains mostly to remove the suspicion that the refs might be fudging the calls to favor specific teams. By planting the back end of the chain and pulling it tight, the determiniation of whether it’s a first down looks scientifically determined.

If the ref just walked onto the field, glanced at the bal and called it a first down or not, fans would go crazy thinking he’s favoring one team or another.

7

Yeah, but whatever the ref did would be no more accurate than the initial setting of the chains and he could readily favor a team that way. It is basically a charade to lend an air of accuracy to what is inherently inaccurate. Even more inaccurate than the setting of the chains (which is probably within an inch or so) is the official determination of where the ball was when some part of the runner’s body other than foot or hand first touches the ground. I bet that can be off by a foot or so.

8

In youth and high school ball(not sure about college 'cause my kid’s not there yet), the ‘box man’-the guy with the down marker stick, also has the responsiblity to put a little orange plastic tag on the chain at the closet 5 yard mark to the end of the chains. He does this at the beginning of down 1.

The chain gang is encouraged to drop the sticks whenever the action approaches the sideline to avoid injury to the players. The tag helps in replacing the sticks on the sideline as well as placing the sticks on the field.

9

In fancy places, there is a guy whose job it is just to place the tag on the chain!

But I think the OP should accept the fact that measuring for a first down with any sort of precision is really a sham, but we all buy into it, so there’s no harm done.

10

Sure, the referee’s marking of the place where the ball was down is way more inaccurate in some cases than the chain measurement. Nobody expects precision surveying. Wherever the referee marks the ball is the place where it should be, by definition, and everything starts from there.

11

The game of football is almost entirely played around rules and technicalities (and talent) so I don’t understand why they don’t use technology more when it comes to these things. I would imagine that it would be fairly technologically simple to have lasers marking the spot or perhaps a signalling device in the football and a reciever measuring exact distances. But I guess it’s that inexact part of it that makes the game so much fun too. I’d prefer precision, especially during playoffs and such.

12

They have updated the referee system somewhat to allow “reviews” of certain plays. I always thought the laser idea was a good one too, but you would need all kinds of detection devices. If I understand things correctly, the ball is marked where the ball was positioned at the time the first knee touches the ground. So, you would need detection devices on all the player’s knees too. (Before I start a major debate, there are exceptions to that rule: If the ball breaks the plane of the goal line, etc.).

So it looks like the refs in football, and umpires in baseball, are here to stay, for the time being anyway.

13

I thought of that also but just in the case of spotting the ball after a play with respect to right angles of the sideline, lasers would be an aid.

And a signalling device in the football would be a perfect dertermintation of whether the ball breaks the plane of the goal line.

My point is that the officiating can be so very off sometimes that it couldn’t hurt in a technical game to keep up with technology.

14

I can tell NONE of the previouse posters have played football…

First of all football fields are NOT flat…They are level end to end but NOT side to side,(for drainage purposes).
They have a crown that would render a laser inoperable at least at ground level from sideline to sideline.

Actually the only call that can be questionable by a fan is the SPOT the ref decides is placed… That is done by human judgement.

I can’t see where it could get any better as long as ALL officials are impartial…

15

I think the Rose Bowl has a flat field because it is used for soccer frequently, but most fields do have a crown.

But when you watch a running back jump over the line and into a big pile at the line and the linesmen runs in and says “He was down … HERE!” I would say that’s a lot of guesswork.

16

Check out this link. Click on “General Instructions for line-to-gain crews”. It’s high school, but I would guess its the same regulations.

Side issue: you wouldn’t need lasers to do this accurately. An infrared emitter in the football, and a few sensors around the stadium could exactly determine where the first down mark is. That technology is simple. For instance, similar technology was used for FOX NHL broadcasts with the Foxtrax “glowing puck” a few years ago. They were able to exactly pinpoint the location of the puck and digitally add the blue glow. And that was in real time. There’s not even really any guess work as I understand the technology. It’s just a matter of detecting the infrared signal and triangulating the position. Cite

When a team gains a first down, some judgment is still needed in determining where the spot is, but once the ball is set, a signal would be sent indicating “10 yards from this spot is first down.” Then, another judgment call is made on the spot of the ball after a gain, but after the ball is placed, the error associated with the linesman moving to the sideline, and the error associated with moving the chains from the sideline to the field is removed.

Chains could still be kept on the field, but as a reference for fans at the game only.

17

I remember in Lincoln Nebraska many years ago, the guy on the back end of the chains was caught rolling up the chain on the back pole. Eighty thousand people watching in person and no telling how many on TV, but every one of them was watching the front marker, to see if they made the first down, and nobody saw the back guy shortening the chain … for a while anyway!

These are dark days for Cornhuskers, maybe we should start that again.

18

Craneop2, your assessment of the football-playing backgrounds of the posters is wrong. I have played football, and I’m the one ignorant enough to ask the question in the first place. But two years in high school obviously wasn’t enough for me to figure out the intricacies of officiating.

But I don’t see what the crown of the field has to do with anything. I don’t see how it answers or shoots down any of the questions in my post. Besides, you don’t have to have played football to know that there’s a curve to the playing surface. In most stadiums, it’s readily apparent from the stands.

And as for the laser…there are practical solutions already developed. This company was featured on TechTV a couple weeks ago (printed story). Obviously the curve of the field isn’t a problem for them. They’re just battling for league approval now…but the proof-of-concept is there.

Then again, I wasn’t too worried about what the zebras were doing with the chains when I played football. I was too busy trying to avoid getting hit. Then I switched to defense, but still didn’t think too much about the chains. I was too busy sucking.

19

When I retire, I’m determined to get a job as the chain-guy! Been a dream for several years now. What a way to see all home games up close?

20

That’s cool. I think it would be a good tool for marking the ball after the play but not for use during gameplay itself because that would be like having goal lines all over the field.