A bumps race is a multi-day race beginning with crews lined up along the river at set intervals. They start simultaneously and all pursue the boat ahead while avoiding being bumped by a boat from behind. If a crew overtakes or makes physical contact with the crew ahead, a bump is awarded. As a result, damage to boats and equipment is common during bumps racing. To avoid damage the cox of the crew being bumped may concede the bump before contact is actually made. The next day, the bumping crew will start ahead of any crews that have been bumped. The positions at the end of the last race are used to set the positions on the first day of the races the next year. Oxford and Cambridge Universities hold bumps races for their respective colleges twice a year, and there are also Town Bumps races in both cities, open to non-university crews. Oxford's races are organised by City of Oxford Rowing Club and Cambridge's are organised by the Cambridgeshire Rowing Association.
The rowing machine itself is unlike any other on the market with its patented water filled flywheel. It is hard to exactly copy the action of a scull on the water, but the mechanics of the flywheel spinning in water comes in a close second on dry land. The fact that the water is 800 times denser than air means that there is no need for any extra resistance or dampening that you will find in normal air rowers. The faster you pull, the more resistance is generated giving it infinite variability. However, if you want to be able to practice rowing with a faster stroke, you will have to reduce the amount of water in the tank unlike an air rower where you just have to adjust the baffle.