Question: What sport do both Isabel Letham and Duke Kahanamoku have in common?

full_context: Document 1: Linda Beilharz: Linda Beilharz, OAM, is an Australian adventurer who is the first Australian woman to successfully trek the South and North poles. She completed the North Pole expedition with her husband Rob Rigato and Canadian explorer Sarah McNair-Landry in April 2010 while the South Pole feat was completed in December 2004 when she became the first Australian woman to ski 1,100 km from the edge of the Antarctic to the South Pole.
Document 2: Dorothy Levitt: Dorothy Elizabeth Levitt, (born Elizabeth Levi; 5 January 1882, died 17 May 1922) was the first British woman racing driver, holder of the world's first water speed record, the women's world land speed record holder, and an author. She was a pioneer of female independence and female motoring, and taught Queen Alexandra and the Royal Princesses how to drive. In 1905 she established the record for the longest drive achieved by a lady driver by driving a De Dion-Bouton from London to Liverpool and back over two days, receiving the soubriquets in the press of the Fastest Girl on Earth, and the Champion Lady Motorist of the World.
Document 3: Wendy Botha: Wendy Botha (born 22 August 1965) is a four-time world surfing champion. She won her first title as a South African citizen in 1987, then she became an Australian citizen and won three more titles in 1989, 1991, and 1992. She also posed nude for Australian Playboy for the September issue of 1992.
Document 4: Women's athletics in Australia: While not being urged to avoid competition, women had few opportunities to compete in sport in Australia until the 1880s. After that date, new sporting facilities were being built around the country and many new sport clubs were created. Athletic events were being held in schools in Australia by the early part of the twentieth century. The Glennie School in Toowoomba was one school to host races for girls during their annual girls' sport day. During the 1920s, girls were able to run while wearing bloomers, instead of skirts. The first meeting for women's athletics took place in 1926 and was organised by the NSWAAA. The purpose of the meeting was to determine if it would be possible to send women to compete in the 1928 Summer Olympics based on merit. Only one female athlete was determined to be good enough to send. That was E.F. Robinson. The first women's national athletics body designed to govern the sport in Australia was founded in 1932 and was called the Australian Women's Amateur Athletic Union. It was designed to oversee state organisations in Victoria (1929), Queensland (1921), New South Wales (1932) and South Australia. (1932) The first Australian woman to travel overseas to compete was E.F. Robinson, who went to the 1928 Summer Olympics where she ran in the 100-metres. She came in third and was the only Australian female on the 1928 Australian Olympic team.
Document 5: Duke Kahanamoku Invitational Surfing Championship: The Duke Kahanamoku Invitational Surfing Championship is named in honor of the "Father of Modern Surfing", Duke Paoa Kahinu Mokoe Hulikohola Kahanamoku. The contest began in 1965 by invitation only at Sunset Beach on the North Shore of Oʻ ahu until it was replaced by the Billabong Pro in 1985. The championship was the first surfing event to be broadcast on a regular basis by ABC's "Wide World of Sports".
Document 6: Hoolulu: Hoʻolulu (1794–1844) was a member of the nobility during the formation of the Kingdom of Hawaii. He was a trusted advisor to King Kamehameha I, also known as "Kamehameha the Great", and was one of the select few to know his secret resting place. His descendants continue the tradition of guarding royal burials. A major cultural site in Hilo, Hawaii is named after him.
Document 7: Isabel Letham: Isabel Letham (23 May 1899 – 11 March 1995) was an Australian pioneer surfboard rider and swimming instructor, renowned as 'the first Australian to ride a surfboard' (although she disputed that claim - Isma Amor of Manly is believed to be the first Australian Female Surfer and Tommy Walker of Manly is believed to be the first Australian Male Surfer). A probably erroneous story has been repeated for years that on 10 January 1915 at Freshwater Beach, Sydney she experimented riding a board in the Hawaiian tradition in tandem with Duke Kahanamoku. This story has been disputed by researchers who have investigated its roots and provenance, and the reality is probably that she did not do so until shortly after, at Dee Why beach in Sydney, on February 6, 1915.
Document 8: Butch Van Artsdalen: Charles M. Van Artsdalen (January 31, 1941 – July 18, 1979) was a legendary surfer. He moved to La Jolla, California, from his birthplace of Norfolk, Virginia, at age 14. Van Artsdalen is best known as a pioneer of surfing 25-foot waves at such North Shore locations as Waimea Bay and Sunset Beach; and tube riding in Hawaii during the early 1960-1970s. A member of the Duke Kahanamoku Surf Team, he appeared in several surf movies and remained a fixture of the international surfing community until his death from alcohol-related illness in 1979.
Document 9: Jim Leytham: James Leytham (birth registered October→December 1879 – 20 August 1916) birth registered in Lancaster, was an English professional rugby league footballer who played in the 1890s, 1900s, and 1910s, playing at representative level for Great Britain, England, and Lancashire, and at club level for Lancaster, and Wigan (captain), as a wing , i.e. number 2 (number 14 in a 15-player team) or 5 (number 11 in a 15-player team). Leytham along with several members of his family died in a fishing accident in the River Lune Estuary, Morecambe Bay on Sunday 20 August 1916, his death was registered in Lancaster
Document 10: Watersun Swimwear: Watersun Swimwear is the oldest privately owned Australian swimwear and beachwear manufacturer. Established in the mid-1950s, Watersun has been synonymous with the Australian way of life in terms of Swimwear and Beach Fashions for nearing half a century. Its trademark Graphic Glamour Swimsuit Designs of the '60s, '70s and '80s were recently displayed in the Australian National Maritime Museum which paid tribute to the History of Australian Swimwear: Exposed! The Story of Swimwear.
Document 11: International Surfing Museum: The International Surfing Museum is a non-profit, 501(c) museum in Huntington Beach, Orange County, California. The museum's goal is to preserve the history of the surfing culture throughout the globe. It is dedicated to Duke Kahanamoku, who is generally regarded as the person who popularized the modern sport of surfing.
Document 12: Ken Bradshaw: Ken Bradshaw (born October 4, 1952) is an American professional surfer and winner of the 1982 Duke Kahanamoku Invitational Surfing Championship.
Document 13: Bethany Hamilton: Bethany Meilani Hamilton-Dirks (born February 8, 1990) is an American professional surfer who survived a 2003 shark attack in which her left arm was bitten off but who ultimately returned to—and was victorious in—professional surfing. She wrote about her experience in the 2004 autobiography "Soul Surfer: A True Story of Faith, Family, and Fighting to Get Back on the Board". In April 2011, the feature film "Soul Surfer" was released.
Document 14: Eddie Aikau: Edward Ryon Makuahanai Aikau (Kahului, Hawaii, May 4, 1946 – March 17, 1978) was a well-known Hawaiian lifeguard and surfer. The words "Makua Hanai" in Eddie Aikau's full name mean "feeding parent", an adoptive, nurturing, fostering parent, in the Hawaiian language. As the first lifeguard at Waimea Bay on the island of Oahu, he saved over 500 people and became famous for surfing the big Hawaiian surf, winning several awards including the 1977 Duke Kahanamoku Invitational Surfing Championship.
Document 15: Duke Kahanamoku: Duke Paoa Kahinu Mokoe Hulikohola Kahanamoku (August 24, 1890 – January 22, 1968) was a Native Hawaiian competition swimmer who popularized the ancient Hawaiian sport of surfing. He was born towards the end of the Kingdom of Hawaii, just before the overthrow, living into statehood as a United States citizen. He was a five-time Olympic medalist in swimming. Duke was also a law enforcement officer, an actor, a beach volleyball player and businessman.
ground_truth: surfing