IRA Heavyweight Grand Final = lesson in rowing physics

The Intercollegiate Rowing Association (IRA) national championships took place this past weekend at Lake Natoma, near Sacramento, CA.  One of the big questions was whether the University of Washington, which had swept all events at the NCAA womens’ championships a couple of weeks ago, would also sweep all of the men’s events at IRAs.

Yale, the most dominant crew in the East, led at the start and by as much as a length through the middle of the race.  The question was whether they could withstand the Husky sprint.

They did, by .069 seconds.  This photo illustrates why.

The boats are basically even but Yale (background) is approaching the finish of their last stroke while Washington (foreground) is still mid-drive.  While both crews are going really fast (sub-5:30 for 2k), boats do not maintain a linear speed in rowing, but accelerate and decelerate during each stroke as power is applied and the combined body weight of the crew moves on sliding seats relative to the hull.  Yale is about to enter the fastest portion of the stroke where all the power has been applied, the blades come out of the water, and 8 200-lb. bodies slide to the stern, which due to Newton’s laws means the hull surges forward at its fastest speed.  Washington is still halfway through the drive, meaning that the force applied to the blades is being transferred through the footplates in the sternward direction, and the “rebound” from that force has not yet happened.

This means that within the next split second, Yale’s boat will surge forward before Washington’s, and that makes all the difference when the margin is literally the blink of an eye.  For CrossFitters who have never been in a boat, try rowing on a dynamic ergometer or a C2 on sliders to feel this effect.

Congrats to both crews on an amazing performance, to Cornell for winning the lightweight men’s championship, and to Stanford for winning the lightweight women’s championship, and to Washington for winning the overall points trophy.  Congrats to my alma mater Dartmouth for winning the Chapman trophy for the greatest improvement in points year over year.  Thanks to for great coverage as always!

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