Overview
The racing takes place on the Isis, a length of the River Thames, which is generally too narrow for side by side racing. For each division, thirteen boats line up at the downstream end of the stretch, each cox holding onto a rope attached to the bank, leaving around 1.5 boat lengths between each boat. The start of racing is signalled by the firing of a cannon, each crew attempting to progress up their division by bumping the boat in front, while avoiding being bumped by the boat behind. Once a bump has taken place, both of the crews involved stop racing and move to the side to allow the rest of the division to pass. It is possible to 'over bump' if the 2 crews in front of your boat bump (and so drop out) and your boat can catch the boat that was in front of them. They then swap places for the next day's racing, whether that be the calendar day or the first day of racing in the next year's competition.
The ultimate aim of a crew is to become "Head of the River" (top of the first division) and stay there. This entitles the winning crew to commission trophy oars in their college colours with the names and weights of the successful crew on them — commonly called 'winning blades'. As this is only possible for crews already near the top of division one, another way to win blades is to bump on each day of the competition. As the responsibility for awarding blades to crews rests with the individual colleges concerned, there are slight differences in the criteria required.
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