Swimming vs. Tide Surfing around Manhattan

It’s well known that Shelley Taylor-Smith holds the record for the fastest swim around Manhattan: 5 hours, 45 minutes, 25 seconds.

What’s not quite as well known is that she achieved this feat on a special “fast tide” - a convergence of maritime conditions in the East, Harlem, and Hudson Rivers that occurs only once or twice a year, if at all.

With the founding of the modern Manhattan Island Marathon Swim race in 1982, and more sophisticated understanding of tide cycles, a string of specially planned solo “record attempt” swims were undertaken in the ’80s and ’90s, all on fast tides. After Diana Nyad‘s 1975 swim in 7 hours, 57 minutes, the record was lowered six times by four different people over the next 20 years:

Her record has stood ever since, despite an assault last year by world-class marathon swimmers Petar Stoychev and Mark Warkentin.

To give a sense of how much the tides matter in these swims, Taylor-Smith’s 5:45:25 works out to a pace of 45.2 seconds/100m (12.1 minutes per mile - almost 5 mph). If you assume a 20 minutes/mile average swimming pace (world-class for marathon distance), that means she derived 40% of her overall speed from the river currents!

All this is by way of saying: There’s a reason nobody ever comes close to 5:45 in the annual race. MIMS is never held on the special “record attempt” tides. Why not? Though I haven’t seen this stated explicitly anywhere, I assume it’s because while the “record attempt” tides may push a fast solo swimmer around Manhattan very quickly, it may not be suitable for getting a group of swimmers (of varying speeds) around Manhattan in a reasonable amount of time. The “MIMS tide,” as I understand it, is actually selected to punish the fastest swimmers with head currents (they arrive at Spuyten Duyvil ahead of the tide change ). As a result, the MIMS field tends to compress much more than would a current-neutral swim of similar distance.

So basically, the MIMS race and the special “record attempts” are two entirely separate categories of swims. We all know that 5:45 is the fastest overall swim, but that was on a “record attempt” tide. What are the fastest swims on the regular MIMS tide?

NOTE: Much useful information in this post was gleaned from Capt. Tim Johnson’s wonderful History of Open-Water Marathon Swimming.

Posted 14 April 2011 in: analysis Tags: data , MIMS