After completing the Avalon Swim, I was pondering whether seeded waves would work, where swimmers are sent off in times according to their 1km swim times.
Being of the pointy-head variety, I had to satisfy my curiosity with some analysis of the results to see if seeded swims would work, and even out the flow of swimmers around the course.
The chart below shows the numbers of swimmers in 2 minute increments according to their finishing time. For those fellow pointy headed swimmers, you will note that half of the swimmers have completed the swim by 28 ½ mins time and that the results are skewed, with a tail of slower swimmers.
This info shows that if starts were based on seeded times with equal time classes, then there would be some groups much larger than others. Seeded starts might work if the times were worked out such that waves were based on achieving equal sizes.
If the organisers were to achieve say, 5 waves of 200 persons each then seeding would have to be based on 1 km swim times as follows:
• < 18 mins per km • 18 – 19 ½ mins per km • 19 ½ to 21 mins per km • 21 to 23 ½ mins per km • >23 ½ mins per km
With age group wave starts, it is near impossible to group waves into equal size classes. The table below shows the number of swimmers by age group category.
This info shows that grouping the swimmers into equal size groups would be very awkward. For example, there were 337 swimmers between 35-45 yrs of age, so you can get a feel for the issue.
In short, I don’t envy organisers of swim events in trying to sort out wave starts. People say, “more waves”, but while the waves are set out in age groups, it will never cut the argy bargy as swimmers’ abilities are not age dependent (if you have raced John Koorey, you will understand what I mean!)
Seeded waves would work but would require honest assessment of one’s swimming abilities and a reasonable analysis of previous events’ results to assess time categories and wave numbers.