What's the longest butterfly race you could swim?

I've always been intrigued by those people who do extreme long distance butterfly, like Vicky Keith. (Not that I'm ever planning to try something like that, I'm just amazed that it can be done!) Has anyone ever seen someone doing that, or know of an online video clip? Is the stroke done somewhat differently to be able to last so long? There used to be an online club called the Butternuts, for people who had done at least 500 continuous meters of 'fly. I tried to find it yesterday and just got a whole bunch of horticultural sites about walnut trees. A Chicago swimmer typically does the 5k Big Shoulders swim all butterfly. I'll see if I can find his Web site, then you can ask him many questions! Here's his author's bio on Amazon: www.amazon.com/.../192980900X Regards, VB

Here's a meet for people who like long fly: www-ee.stanford.edu/.../ Read, especially, the history: www-ee.stanford.edu/.../History.pdf Best time in the 1650 fly at this meet seems to be: 20:11.78