Summer Eights is a bumping race held on the Isis in Oxford over 4 days usually on the 5th week of Trinity term (in May).


Crews start lined up with about 1.5 boat lengths between them. After a canon is fired, the crews attempt to catch ("bump") the boat in front of them. When a bump occurs both the bumped crew and the bumping crew stop racing. This is the major difference with Torpids where the crew that has been bumped has to keep on racing.


The aim is to bump up in the rankings to finish at the top of the first division: "Head of the River". The rankings carry on from year to year, with the starting order of one year being based on the finish order of the previous year. Crews who manage to bump on every single one of their races during the 4 days are awarded blades: The crew members have the right to buy a blade painted to their college's colours and showing and their names and their college's crest.