August 26, 2010

There are innumerable ways to row boats, but mathematical physicist John Barrow (University of Cambridge) has made a splash by optimizing the ways to arrange the port and starboard rowers in racing boats. He's discovered arrangements in four- and eight-person rowers whereby the rowing forces are wiggle free.

The conventional rig, in which the port and starboard rowers alternate, results in energy-wasting, side-to-side wiggle (oscillating, non-zero transverse moment) as the rowers move up and down the hull on every stroke.

Barrow showed that the problem of finding zero-moment rigs is related to a special case of the subset sum problem. He found the one (known) zero-moment rig for a racing four, and showed there are four possible rigs for a racing eight, of which only two—the so-called Italian and German rigs—appear to be known to sportsmen.

Barrow then generalized the idea for any number of crew members, proving that crew numbers divisible by four can be wiggle-free; and he showed that unbalanced boats in which there are unequal numbers of oars on each side could also be wiggle free.

"Ive never rowed competitively," said Barrow, "but I'm fascinated by the links between mathematics and sport."

New Scientist tested Barrow's theories on the Thames. Consulting editor Justin Mullins described the results in The Washington Post.

Read more about Barrow’s work here.