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Slalom Survey Errors

Posted: Thu Jan 20, 2022 4:10 am
by LakeHoodNZ
I have attached a slalom survey for a site I am currently working with. The software reports 4 errors, Axe - B1, Axe - B2, Average B1-B11 and Average B2-B12. Each of these measurements appear to be within the minimum and maximum tolerances stipulated in the program but are shown as errors. Are the actual tolerances much tighter than those shown for these measurements? Kind regards, Richard.

Re: Slalom Survey Errors

Posted: Fri Jan 21, 2022 9:56 pm
by emmanuel
Hi Richard,

I don't see any attached file...

But yes, there is an additional IWWF rule 25.08 b) which tighten guide boat buoys tolerances (recommended in 2021) :

b) Slalom
1. The centreline is a line from the middle of the entry gates to the middle of the exit gates.
2. Each boat guide (B1…B12) has a width (distance from centreline/axis) tolerance of +/-11.5 cm, but
the left side (B2,B4,B6,B8,B10,B12) and the right side (B1,B3,B5,B7,B9,B11) must each be visually
straight. To ensure that each side is straight, it is recommended that each individual boat guide
distance/width from the centreline/axis (1.15) is within 4cm of the average boat guide
distance/width for that side.
(Example: Axis-B1=1.15, B3=1.16, B5=1.12, B7=1.18, B9=1.15, B11=1.17; Avg.=1.155 (Meets
3. To ensure that the visual centreline (axis), as seen from the boat guides, is equal to the calculated
centreline (axis), the difference between the average boat guide width on each side should not be
more than 4cm.
(Example: Axis B1-B11 Avg =1.155; Axis B2 -B12 Avg=1.20 (Does not meet requirement).


Re: Slalom Survey Errors

Posted: Sat Jan 22, 2022 5:39 pm
by LakeHoodNZ
Thank you very much for your answer to my query, Emmanuel. I now understand how these measurements are calculated and the reasons for their inclusion. Kind regards, Richard.