Embrun starts in the dark...
there are boats with lights on the lake.

there may be a (serious) lawsuit potential if you did this in the US, but in Europe, it should be fine.
maybe email the organizers in Embrun and ask them how they do.

Congratulations on pulling off your race. However, you may need to rethink your claim to the "world's roughest ironman distance". The Mountain Extreme Triathlon (www.mxtri.com) was staged this past July 12th, and was truly brutal. There were 152 starters, and only 68 finishers! There was a 24 hour cutoff, and the top finisher came in at 15:01:39, and the fastest bike split (and this was by a pro) was 9:00:02. Many took over 14 hours to complete just the bike course (which included more than 9000 feet of climbing), and many took up to 8 hours to complete the run. The last finisher came in at 23:41:52.

There was a "Mini" (Half Iron distance) contested at the same time, and two of the finishers in that event took over 20 hours to finish...FOR A HALF!!!

One competitor deserves special mention. John Tucker, of Park City, UT (originally of South Africa), finished in 8th place overall with at time of 17:09:08, just 12 days after going 11:10 at Ironman Coeur d'Alene!

BTW, in response to your specific question. This event started at 6am, which was just before sunrise, so technically "in the dark". Also, maybe you can keep your claim to "world's roughest" if you modifiy it to "on road", as the Mountain Extreme was Off-Road" the competitors rode mountian bikes, and ran on trails.

Ironman NZ starts almost in the dark...just as the sun is rising and if it's cloudy, it's effectively dark.

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clm
Nashville, TN
https://twitter.com/ironclm | http://ironclm.typepad.com

no no no no no no no no no no no no no!!!!!!!
a dark swim is too dangerous. i don't care how many lights and boats you have out there open water is nothing to screw with. i have done tons of open water night swims, with navagation aids and wet suits and never liked the odds. put a pack of swimmers in the mix and it's a nightmare.

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