What are you using for tracking for 24 hr races?
Also curious, but I suspect Joe's nav is so good he just remembers where he was on the map at 5-second intervals and then draws in the tracklog at home.
Suunto ambit run. Programmable for different sports. You can vary the sample interval and the gps accuracy to extend the record time. I have an AR mode that records every ten seconds and uses a less accurate gps and it only used 24% of the battery in 22:30 hours. You can also modify the screen settings so no distance is shown. I only have total time, time of day and altitude.
i think danfoster's theory is correct and the ambit is just a cover.
Thanks Joe. That sounds far better than other options I have explored.
Nice watch! Just a note that the Garmin Fenix 3 has a similar mode.
I used it on a backpacking trip last weekend and after about 17 hours of GPS mode and the rest of the time running it as a regular watch it had eaten about the same amount of battery as the ambit. The ambit does cost less than the Garmin