"Because one of my ancestors decided to walk upright, I (and half of the other 6 billion people on the planet) am prone to back pains that, of course, become acute just before an important race. Thus, in 1982, during a typical rainy Rinconada meet I had to face a 1650 free half-doubled up by a complaining L4 vertebra. It happens that Brazilians will not settle for small disasters - we always try to make them worse. Seeing no way of finishing the race, I had the stupid idea of doing a few laps of butterfly before quitting. At the 150 yard turn, my back gave up (but I did not): the pain went completely away. Not daring to stop, I did the rest of the race all in butterfly and discovered the fundamental law governing that stroke: if you can survive the first 300 yards, endorphins take over and not only numb your pain but also your mind and you can keep going forever (not really!).
Uninitiated swimmers in the audience were awed by the feat prompting Rinconada to offer the same opportunity to all (insane) comers by including, every year, in our Spring Meet the 1650 Borboleta (that's "butterfly" to you few swimmers who are not fluent in Portuguese).
These days, if you see me on the deck instead of elegantly sailing through the water in that event, it is only because my psychiatrist has strictly forbidden me to swim it.
In 1983, the first Borboleta year, the best time (regardless of sex) was San Mateo Marlins's Marianne Brems's 24:55.61. The oldest swimmer (and still the age group record holder) was Walnut Creek's Ella Peckham (then 83 years old) who did it in 64:10.32. Ella had never done a 1650 free!
Female dominance lasted until 1987 when, finally, Steve Breiter (Walnut Creek) did an extraordinary 21:03.07, followed next year by a even better 20:38.55, a record broken in 1988 by Darren Phelan of the San Francisco Recreation and Parks club (20:14.31).
One should not fail to mention the amazing performance of Lorraine Sommers (SCAM) who swam the event 8 times over the span of 11 years. In 1984, when she was 27 years old, she did 23:00.25 and in 1995 at the age of 38, her time was 23:02.24. Less than 2 seconds decay/decade!
Defending the male team, we have Charles Bannan who has swum the Borboleta for a record of 10 times (Update: as of 2016 Charles swam it 23 times!). He only missed 1998 because the Rinconada pool was being repaired and the event was not offered.
The loping fly stroke required for such a long event is the best prescription for destroying your sprinting ability. Ann Kay who swam in 1983, needed 5 years to recover her, previously fast, 50-fly performance!
When first introduced, the butterfly stroke was thought by many as a rival to the "crawl" as the fastest way for a human to propel himself (herself?) through water. Nevertheless, any mechanical engineer could have predicted that such expectation would be wrong: the intermittent butterfly pull results in a greater average drag than the smoother and more continuous crawl. The "fly" is now considered a fast but uneconomical stroke effective only over short distances. Indeed, many have discovered the meaning of the "piano on your back" when pushing too hard and too early in a butterfly event. The Rinconada 1650 Borboleta (offered yearly in the spring) proves that butterfly can be used over long distances by even moderately good swimmers."
1917 - 2015
On the photo: Charles Bannan (left) and Aldo da Rosa (right), March 2008