I would like any suggestions on how to do this with a tape. (This is pretty non controversial, right?) I have spent a career trying to figure out how to measure things, and I am curious. From the comments in this group, the problems I mention below must have been solved.
First you stretch the tape along the side of the pool. That would work well, but how are you sure you are aligned with the walls, or that the walls are square? Also, you need to measure in several lanes, rather than the side.
So you get in the pool and hold the tape against the walls, 1 foot below water level. The problem is that the tape sags, and any measurement will overestimate the length of the pool by a significant amount. You could pull the tape tighter, but I suspect before the tape gets tight enough, your tape will stretch or break. (I used to assign that as an intro physics problem). I suppose you could build a support structure across the pool, but that would be a pain in the neck, and you would have to move it from lane to lane.
Getting the water out of the pool would make that support structure easier, but the water weighs a lot. It almost certainly causes the walls to bend outward, especially in the deeper pools. (How do the people who design above ground, temporary competition pools do it?) I don't know how much the walls will move, but how do you account for that? (and by the way, how do the masons make sure their plaster/tiling is correct in an empty pool?)
Here is an idea - you lower the water level by a foot or so, and build a *floating* support structure for the tape. I think that would solve most of the problems. Has anyone done that?
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Originally posted by Howard
The added cost of up to 700+ per meet might be enough to keep a smaller local meet from actually being held. I don't know who wrote the original rules but it may be that they didn't want to write them in such a way that the meet host was going to have to face the choice of having the meet or having the pool measured. On the other hand, given the way it's written and how hard it is to accurately measure with a tape it's questionable if the results are worth the paper they are written on.
You got my point there!!!
One of the things I have to do, that I haven't gotten around to yet is figure out just how much time difference an inch or half an inch or few milimeters make, time wise at certain swimming velocities, and from there come up with a reasonable set of tolerances in the pool length measurements.
Measurements will NEVER be exact, there is always some slop in them. The important part is to come up with an acceptable +/- tolerances. Yes, that would mean that some of the finishing times cary a certain level of uncertainty.
There is a a large volume of literature written on 'error theory' and how to make adjustments for them etc... Something I had to study at length for the business I'm in.
One of toughest thing for 'lay' people to understand is that the measurements and results will never be 'exact', but that they're still good, and comparative.
Explaining all this in detail can be a very lengthy process... I wouold like to, but I really can't afford the time to get into an in depth discussion about it here. I'm sorry.
Originally posted by Howard
The added cost of up to 700+ per meet might be enough to keep a smaller local meet from actually being held. I don't know who wrote the original rules but it may be that they didn't want to write them in such a way that the meet host was going to have to face the choice of having the meet or having the pool measured. On the other hand, given the way it's written and how hard it is to accurately measure with a tape it's questionable if the results are worth the paper they are written on.
You got my point there!!!
One of the things I have to do, that I haven't gotten around to yet is figure out just how much time difference an inch or half an inch or few milimeters make, time wise at certain swimming velocities, and from there come up with a reasonable set of tolerances in the pool length measurements.
Measurements will NEVER be exact, there is always some slop in them. The important part is to come up with an acceptable +/- tolerances. Yes, that would mean that some of the finishing times cary a certain level of uncertainty.
There is a a large volume of literature written on 'error theory' and how to make adjustments for them etc... Something I had to study at length for the business I'm in.
One of toughest thing for 'lay' people to understand is that the measurements and results will never be 'exact', but that they're still good, and comparative.
Explaining all this in detail can be a very lengthy process... I wouold like to, but I really can't afford the time to get into an in depth discussion about it here. I'm sorry.
