Complex sentence: Wayne Pommen, the first-choice Cambridge bow-man, was injured two days before the race, breaking his wrist in a collision with a harbourmaster's launch, and was replaced by Ben Smith, brother of the Oxford stroke Matthew.
Split into simpler sentences: Wayne Pommen, the first-choice Cambridge bow-man, was injured two days before the race, breaking his wrist in a collision with a harbourmaster's launch. Pommen was replaced by Ben Smith, brother of the Oxford stroke Matthew.