H. A. Harnett
Sailor H. A. Harnett (or Hartnet) died of injuries sustained during a January 14, 1908 bout with Sailor Manning at Newport, Rhode Island, USA.
The men were apprentice seamen assigned to the training ship, USS Cumberland (IX-8). They had a grudge, and agreed to fight it out under supervision. Gloves were worn, a referee was in the ring, and the surgeon sat ringside. Both boxers were visibly tired by the seventh, and in the eighth, Harnett was knocked down. He did not get up, and he died in hospital on January 18. Cause of death was a blood clot on the brain. The commanding officer of the USS Cumberland received an official reprimand for allowing apprentice seamen to settle a dispute with boxing gloves.
Source: Death under the Spotlight: The Manuel Velasquez Boxing Fatality Collection [1]