Ru den Hamer
From Wikipedia, the free encyclopedia
Rudolf "Ru" den Hamer (born July 24, 1917 in Buitenzorg, Dutch East Indies - died March 14, 1988 in The Hague) was a Dutch water polo player who competed in the 1936 Summer Olympics.
He was part of the Dutch team which finished fifth in the 1936 tournament. He played four matches.