Crocodile XC park MTBO
By Joolz - Mon 21 Dec 2020 9:13am
Man and son with bikes looking at map

When asked if I would control an MTBO event at Halswell Quarry in Christchurch I envisioned an event traversing the open spaces of the Quarry Park with a few controls on the Crocodile and C2 MTBO tracks. Clearly I hadn’t been mountain-biking there for a couple of years or been in the park on a Sunday afternoon either. Suspicions were initiated when requests for an MTBO map of the park were unanswered, began to be raised at the school champs when there were reports that new tracks in the forest hadn’t been mapped, were heightened at the Night Nav event when nothing made much sense while trying to make sense of the mapped tracks in the dark, and confirmed when I went for a ride around the park on a warm Sunday afternoon. The number of people out for a stroll, the dogs chasing my bike in the dog park, the no bikes signs on some tracks and a chat to the ranger confirmed that the Quarry Park was not an option. Meanwhile the proliferation of tracks and numerous one-way signs in the Crocodile MTBO park, had me doubting if that area would be feasible either. Fortunately a very good map of the MTB tracks on a sign at the park provided a good basis for initial conversion of the foot O map to MTB specs with direction arrows added. Contour interval was changed from 2.5m to 5m improve legibility, and printing on A3 at 1:2500 scale showed that the map, although somewhat confusing, could be read. Some further updates were added from Ryan Moore’s Van Asch farm re-map and field checking.

I advised course planner, Kate Salmon, that an Easy course would have to use the least steep and
easiest to follow trials. Murray from the Singletrack Club, stipulated that for safety’s sake we should avoid placing controls on any steepish downhills. A long conventional course with good route choice would likely result in a confusing multitude of lines criss-crossing the map, so I suggested trying a variation on a score / rogaine type course where there was no time limit, but everyone has to visit all controls. Kate’s initial courses largely met requirements with just a few modifications suggested.

The Easy course at 3.5km and 120m climb seemed reasonable for those with less MTB or
orienteering experience. For the Long Random Order course the main issue was to remove the
temptation for competitors to cheat by crossing between the tracks, which in many places are less than 2 m apart, or riding sections in the wrong direction. For a few controls we hoped that honesty would prevail over temptation. We could not see any obvious best route to collect all the controls, so I added route choice lines in Condes to two totally different approaches. To my delight I found that they were only 200m different in length with similar climb and a total length of approximately 6.3km and climb of 230m should satisfy the experienced bikers.

Circumstances meant that Kate and I did not visit the map together until the Thursday evening
before the event when we decided on the best placement for each control to allow for stopping
where the track was widest and flattest. Maps printed Friday, gear, computers and caravan sorted
Saturday, ready for a later than normal start on Sunday to avoid an early morning event in Halswell Quarry. Overnight rain meant a slightly nervous wait for the 8:00am ranger update to the Port Hills tracks website to see if the MTB tracks would remain open. On site, while a little cold and blustery the weather seemed to be improving, until we encountered a vicious squall while putting out the most exposed controls at the top of the map. We hoped that people would still turn up, and were thankful for the scheduled midday start time. Greg, Josie, Chrissie, Graeme, Alan and Joolz got everything else ready and the competitors arrived. Not that many, but some new faces and a few who had already been running and swimming that morning. We made everyone read a long set of instructions to try to reinforce the MTBO rules and were relaxed in the time that we allowed for course planning. It wasn’t long before Hector and Christina returned from the Easy course in 25 and 27 minutes with Leo later taking out the fastest time just under 22 minutes. Digby and Ryan completed the Long Random Order in just under 27 minutes with only 1 second between them and Fergus only 23 seconds slower.

Plotting up their control order in Condes it appears that Ryan and Fergus had very efficient route choices of under 6.2 km, while Digby must have added an extra loop and he did admit to succumbing to a temptation to skip between adjacent tracks while suffering oxygen debt at the end of his course. The complexity of the track network and the confusing nature of the event meant that some people visited a control twice, while a few miss punched by missing a control or two.

How to plan an MTBO event in an MTB park with a dense network of mostly one-way tracks in a small area.

  1. Blow the map up to 1:2500 to make it legible.
  2. Set an easy course following obvious routes on the least steep trails
  3. Set a longer random order course, similar to a score or rogaine event, but with no time limit
    and a requirement to visit every control.
  4. Look at map and have no idea what is going to be the best route.
  5. Check some different route choices for feasibility and length.
  6. Try to reinforce MTBO rules of not cutting between tracks and obeying one-way rules.
  7. Allow a little bit of course planning time.
  8. Let the young guns loose.
  9. Analyse the results to see that different approaches to route choice can result in very similar
    times and distances.
  10. Find that some of the older folk can’t remember where they have or have not been!

By Alister Metherell, Peninsula and Plains Orienteers

#MTBO #MTBorienteering #bikenavigation #bikenav

About Contributor: Joolz

I call myself an adventuress (but not to godzone standard - OK?) designer, photographer and communicator. Challenging outdoors stuff makes food the other passion. I’ll always take the most torturous route to a control, you’ll only find me if you start looking off the map.

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