As you know, USMS passed a rule that will require us to measure any pool in which we hold a meet, IF we want the times from that meet to count for USMS Top Ten. I'm trying to figure out the best way to do this - what sort of tape to buy, the best method to use, etc. (Can you tell that I'm an engineer?)
I'd like to hear from those of you who have measured pools. What brand of tape do you recommend? What length? (60 meters?) Any idea where I can buy such a tape? Any suggestions for how to get a good (accurate) measurement, especially over a 50 meter course?
FYI, below are the instructions on how to perform pool measurements, taken from the USMS Pool Length Certification Form.
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"A completed form must be on file or submitted with an application for sanction or recognition to your LMSC Sanctions Chairman. For pools utilizing bulkheads, completed forms from each session must be included with results sent to the Top Ten Chairman if the results are to be included in Top Ten submissions.
Measurement procedures:
--Measurements must be conducted using a measuring device with the minimum measuring quality of at least ± 0.005 m (±.0.20 inches or 0.016 feet) over the nominal distance. A laser based measuring device may be used but it must be as accurate as required for steel tapes. Tapes may not be combined to perform the measurements.
--Measurements may be reported in either the English system (feet/inches) or the metric system (meters/centimeters).
Instructions for pool length measurements:
--Measurements must be conducted for each lane. Inspect each end of the pool to insure that it is vertical. If there are any protrusions from the wall into the pool between 0.8 meters (2.5 feet) below the surface to the top of the touch pad or wall or up to 0.3 meters above the surface whichever is higher, you must use the protrusion as your measurement point. Otherwise, measurements must be taken in the center of each lane at water level.
--The measuring device shall be moved up/down and left/right at least 12 inches (unless you are on a protrusion) during each measurement and the minimum distance for each measurement recorded.
--Measurements may be conducted with or without touchpads in place. However, if touchpads are used the pool must still meet the length requirements with them in place.
--Permanent courses need only be measured once unless structural changes have occurred since original measurement.
--For pools with a moveable bulkhead, after each session a course measurement must be confirmed by a responsible person. Only the outside lanes and a single center lane need to be measured to confirm the integrity of the bulkhead and its placement."
Hello, Michael,
We plan to measure our pool with touchpads in place at both ends of the 50 meter pool because that is the configuration that we generally use for long course. If we find the pool is too short, we will measure with touchpads at just one end and discontinue our practice of using touchpads at both ends. World records have been set at our facility and the previous measurements seem to have given us sufficient space for two 8 mm touchpads. We'll see.
While I don't want to promote any particular brand of laser apparatus, an Internet search produced this Canadian website for a LEICA Disto Lite Laser Distance Measurer which is said to be accurate to the millimeter at the distances we require:
www.deakin.com/product.cfm
Aprox. US Price: $449.08
This product was also shown at the following US website, but no price was listed.
www.forestry-suppliers.com/.../View_Catalog_Page.asp
With regard to the coefficient of expansion, an earlier draft of the Guidelines for Pool Measurement included the following information.
"Steel tapes are standardized at 68 degrees Fahrenheit. The coefficient of expansion on most steel tapes is .0000065 ft per ft and average 0.01ft every 15 degrees over a 100 ft distance. If your water/air temperature were around 83 degrees, you would experience a stretch of your tape of 0.01 ft using a 100 ft tape or 0.02 ft with a 200 ft tape. Thus your pool may appear to be shorter than it really is. Record the measurement without correction for temperature. Also record the temperature. Only if your pool measurement comes up short would the temperature factor need to be considered."
We felt this too technical to include in the final version, since the stretch of the tape at higher than the 68 degree standard would not have much impact. The greatest source of measurement error with a tape is sag.
Hope this is helpful.
Hello, Michael,
We plan to measure our pool with touchpads in place at both ends of the 50 meter pool because that is the configuration that we generally use for long course. If we find the pool is too short, we will measure with touchpads at just one end and discontinue our practice of using touchpads at both ends. World records have been set at our facility and the previous measurements seem to have given us sufficient space for two 8 mm touchpads. We'll see.
While I don't want to promote any particular brand of laser apparatus, an Internet search produced this Canadian website for a LEICA Disto Lite Laser Distance Measurer which is said to be accurate to the millimeter at the distances we require:
www.deakin.com/product.cfm
Aprox. US Price: $449.08
This product was also shown at the following US website, but no price was listed.
www.forestry-suppliers.com/.../View_Catalog_Page.asp
With regard to the coefficient of expansion, an earlier draft of the Guidelines for Pool Measurement included the following information.
"Steel tapes are standardized at 68 degrees Fahrenheit. The coefficient of expansion on most steel tapes is .0000065 ft per ft and average 0.01ft every 15 degrees over a 100 ft distance. If your water/air temperature were around 83 degrees, you would experience a stretch of your tape of 0.01 ft using a 100 ft tape or 0.02 ft with a 200 ft tape. Thus your pool may appear to be shorter than it really is. Record the measurement without correction for temperature. Also record the temperature. Only if your pool measurement comes up short would the temperature factor need to be considered."
We felt this too technical to include in the final version, since the stretch of the tape at higher than the 68 degree standard would not have much impact. The greatest source of measurement error with a tape is sag.
Hope this is helpful.
