Stone skipping


Stone skipping and stone skimming are considered related but distinct activities. Both refer to the art of throwing a flat stone across water in such a way that it bounces off the surface. The objective of "skipping" is to see how many times a stone can bounce before sinking; the objective of "skimming" is see how far a bouncing stone can be made to travel before it sinks. In Japan, the activity is called "Mizu Kiri," which translates loosely as "water cutting." Mizu Kiri contests encompass both skimming and skipping principles, as well as a throw's overall aesthetic quality to determine winners.

Championships and records

The North American Stone Skipping Association, founded by Coleman-McGhee, in 1989 and is based in Driftwood, Texas, sanctioned world championships for four years from 1989 through 1992 in Wimberley, Texas. The next official NASSA World Championships is expected to be held at Platja d'en Ros beach in Cadaqués, Catalonia, Spain.
The two primary championships in the USA are at Mackinac Island and Franklin, which happen in July and August respectively. Other major contests include the Vermont Open and the Arkansas Championship, both in September. The domestic championship in the UK is the Welsh, the All England and the British having gone for the present. At present there is also a competition at Ermatingen in Switzerland and occasionally the European in The Netherlands. Results for the various above competitions are invariably to be had online. Japan also holds competitions hinging on various criteria including style.
The world record for the number of skips Guinness Book of Records is 88 by Kurt "Mountain Man" Steiner,. The cast was achieved on September 6, 2013 at Red Bridge in the Allegheny National Forest, Pennsylvania. The previous record was 65 skips, by Max Steiner, set at Riverfront Park, Franklin, Pennsylvania. Before him, the record was 51 skips, set by Russell Byars on July 19, 2007, skipping at the same location. Kurt Steiner also held the world record between 2002 and 2007 with a throw of 40 skips, achieved in competition at Franklin, PA.
A stone skipping championship of a different nature takes place every year in Easdale, Scotland, where relative distances count as opposed to number of skips, as tends to be the case outside the US. Since 1997, competitors from all over the world have taken part in the World Stone Skimming Championships in a disused quarry on Easdale Island using sea-worn Easdale slate of maximum 3" diameter. Each participant gets three throws and the stone must bounce/skip at least twice to count. The WSSC for 2020 were cancelled due to coronavirus concerns. The Guinness World Record for the furthest distance skimmed using natural stone stands at 121.8m established by Dougie Isaacs. For a female it is 52.5m by Nina Luginbuhl. The records were made on the 28th of May 2018 at Abernant Lake, Llanwrtyd Wells, Powys,, Wales

Men's World Skimming Championship winners by year

Women's World Championship winners by year

Scientific explanation

An early explanation of the physics of stone-skipping was provided by Lazzaro Spallanzani in the 18th century.
The stone generates lift in the same manner as a flying disc, by pushing water down as it moves across the water at an angle. Surface tension has very little to do with it. The stone's rotation acts to stabilize it against the torque of lift being applied to the back.
Research undertaken by a team led by French physicist Lydéric Bocquet discovered that an angle of about 20° between the stone and the water's surface is optimal. Bocquet and his colleagues were surprised to discover that changes in speed and rotation did not change this fact, it just allowed the stone to be in balance and to continue with a straight and uniform movement, due to gyroscopic effect. Work by Hewitt, Balmforth and McElwaine has shown that if the horizontal speed can be maintained skipping can continue indefinitely. Earlier research reported by Bocquet calculated that the world record of 38 rebounds set by Coleman-McGhee, unchallenged for many years, required a speed of 12 m/s, with a rotation of 14 revolutions per second.

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