The "elfsteden" tours
Below I present an overview of the 14 tours that were held in the 20th century and after that introduce specific participants in the tour. The table the year, codes for the temperature the quality of the ice, the strength of the wind and an index which the products of the codes of the ice code and the wind code. THis index is a measure of the difficulty of situation was in that specific year. The larger the index the worse the situation was for the skaters. Then follows a column with the number of participants and the percentage of the participants that finished the tour and got a medal..
time The table shows first of all how much the participation in the tour has been increased through the century. In fact there was a stop on the number of participants otherwise the number of participants would have increased even more in the last events because there are now more than 30.000 members of the association of the “Friesche Elfstedentocht”.
We also see in the table that there is a considerable variation in the percentage of participants that have finished the tour in time i.e. before midnight at the same day that they started. In fact this percentage varies between nearly 100% and less than 1%. We don´t see in this case a clear trend in the data that the percentage increases through time: the percentages are sometimes high and low at the beginning and at the end of the series. This suggests that the participants were as capable to finish the tour in the beginning of the century as in the end. This result is very different from the analysis of the time of the winners. My analysis of these data has confirmed this result. The main explanation of the percentage of finishers is by the index (ice x wind) and the temperature during the tour. In this case the following relationship gives a rather good fit to the data:
The percentage (year) = 100% – 8.5% x index(year) - 6.9% x temperature (year)
This means that under ideal weather and ice conditions the percentage of finishers would have been 100% while the index for the combination of wind and ice will reduce the percentage by 8.5% for each point where the index varies from 0 to 9 where 9 is the worse situation. The temperature will reduce the percentage of finishers by 6.9% for each point on a scale from 0 to 3 where 3 is the worse temperature.
So under the worst ice and wind condition the percentage finishers goes down with 76.5% (=9x8.5).
The maximal effect of the temperature is 20.7% (= 3 x 6.9).
The combination of both gives a reduction in the percentage of finishers with 97.2% which is indeed close to the results of 1940 and 1963. In these two tours the ice, the wind and the temperature were so bad that the commission who organized the tour decided to cancel the tour at some point in time in order to prevent more serious accidents then had already happened. In 1963 this meant that people who reached Franeker after 17.00h were not allowed to continue. I was one of the first victims (see “my first elfstedentocht”). The problem was that at many places in the dark the ice and the land could not be distinguished any more due to the snow on the ice. I will illustrate this point by the experiences of one of the participants, Kees Bovée. This problem did not occur to the participants of the race because they started earlier and also finished before it became dark. One can imagine that the tour skaters often suffer more than the participants in the race, not only the former ones are standing longer on their skates but also end up in the dark at last heavy kilometres.
There were also several tours under nearly optimal conditions where close to 95 percent reached the finish in time, especially 1933 and 1942 and the tours with a bit worse conditions like 1941, 1985 and 1986 where nearly 90% reached the finish in time. This seems to suggest that nearly everybody with some skating experience can do it. However as I have indicated in the report about my second Elfstedentocht, in 1986,that was certainly not true. If one has to skate at the end in the dark one cannot see all holes and cracks in the ice and being tired one does not have the coordination anymore to correct the unbalances and so one falls several times and then it is just a matter of luck if one will finish the tour.
Very lucky people were able to skate the tour several times. One of the most famous is Willem Augustin who participated 9 times in the tour. Starting in 1941 he participated in all events after this day. He is such a special person that I will write one of the next sections about him. But I start with another person, Kees Bovée who participated in the tour of 1963 and reported in detail about his experiences during that very difficult tour.
We also see in the table that there is a considerable variation in the percentage of participants that have finished the tour in time i.e. before midnight at the same day that they started. In fact this percentage varies between nearly 100% and less than 1%. We don´t see in this case a clear trend in the data that the percentage increases through time: the percentages are sometimes high and low at the beginning and at the end of the series. This suggests that the participants were as capable to finish the tour in the beginning of the century as in the end. This result is very different from the analysis of the time of the winners. My analysis of these data has confirmed this result. The main explanation of the percentage of finishers is by the index (ice x wind) and the temperature during the tour. In this case the following relationship gives a rather good fit to the data:
The percentage (year) = 100% – 8.5% x index(year) - 6.9% x temperature (year)
This means that under ideal weather and ice conditions the percentage of finishers would have been 100% while the index for the combination of wind and ice will reduce the percentage by 8.5% for each point where the index varies from 0 to 9 where 9 is the worse situation. The temperature will reduce the percentage of finishers by 6.9% for each point on a scale from 0 to 3 where 3 is the worse temperature.
So under the worst ice and wind condition the percentage finishers goes down with 76.5% (=9x8.5).
The maximal effect of the temperature is 20.7% (= 3 x 6.9).
The combination of both gives a reduction in the percentage of finishers with 97.2% which is indeed close to the results of 1940 and 1963. In these two tours the ice, the wind and the temperature were so bad that the commission who organized the tour decided to cancel the tour at some point in time in order to prevent more serious accidents then had already happened. In 1963 this meant that people who reached Franeker after 17.00h were not allowed to continue. I was one of the first victims (see “my first elfstedentocht”). The problem was that at many places in the dark the ice and the land could not be distinguished any more due to the snow on the ice. I will illustrate this point by the experiences of one of the participants, Kees Bovée. This problem did not occur to the participants of the race because they started earlier and also finished before it became dark. One can imagine that the tour skaters often suffer more than the participants in the race, not only the former ones are standing longer on their skates but also end up in the dark at last heavy kilometres.
There were also several tours under nearly optimal conditions where close to 95 percent reached the finish in time, especially 1933 and 1942 and the tours with a bit worse conditions like 1941, 1985 and 1986 where nearly 90% reached the finish in time. This seems to suggest that nearly everybody with some skating experience can do it. However as I have indicated in the report about my second Elfstedentocht, in 1986,that was certainly not true. If one has to skate at the end in the dark one cannot see all holes and cracks in the ice and being tired one does not have the coordination anymore to correct the unbalances and so one falls several times and then it is just a matter of luck if one will finish the tour.
Very lucky people were able to skate the tour several times. One of the most famous is Willem Augustin who participated 9 times in the tour. Starting in 1941 he participated in all events after this day. He is such a special person that I will write one of the next sections about him. But I start with another person, Kees Bovée who participated in the tour of 1963 and reported in detail about his experiences during that very difficult tour.