The 2017 May Bumps will take place from Wednesday 14th to Saturday 17th June with the Getting-On Race on Friday 9th June.
Side-by-side racing is not possible over a long distance on the narrow and winding River Cam, so the bumping races were introduced in the early 19th century as an exciting alternative.
At the start of the bumping races, crews line up, in their finishing order of the previous year, along the river with one and a half boat lengths of clear water between them. On the start signal (the firing of a cannon) they chase each other up the river. When a bump occurs (when one crew is touched by its chasing crew), they pull over to allow the other crews to continue racing. The next day, all crews involved in a bump swap places and the race is run again. After the days of racing, the aim of the top crews is to be at the "head of the river," i.e. to lead the first division. Lower crews cannot expect to achieve this, but can win their "blades" by bumping up every day.
Although the bumps are split into divisions of 17 boats (usually seven in Lents, ten in Mays), the top boat of each lower division (apart from the first division) races at the bottom of the next division (the "sandwich boat") and so a continuous chart can be drawn mapping the progress of all crews.
The Lent (late February) bumping races are run this year over five days but not all divisions race each day. The May races (early June) are run over four days. Bumps Programmes are a great way of finding out about the bumps, and are available to purchase (£4) from King's and some other Porters' Lodges and (during bumps) from the Plough public house and restaurant at Fen Ditton, and from the Control Desk at Peter's Posts, the Chesterton racing marshalling area. The programmes describe the course, race times, crew lists and start order as at the beginning of the week.
More information can be found here.