Complex sentence: Umpired by the Boat Race veteran Boris Rankov, it was the first race to be scheduled on a Sunday, and also featured two sets of brothers, both on opposing sides, for the first time.
Split into simpler sentences: Umpired by the Boat Race veteran Boris Rankov, it was the first race to be scheduled on a Sunday. As such, it featured two sets of brothers, both on opposing sides, for the first time.