Whilst the action of rowing and equipment used remains fairly consistent throughout the world, there are many different types of competition. These include endurance races, time trials, stake racing, bumps racing, and the side-by-side format used in the Olympic games. The many different formats are a result of the long history of the sport, its development in different regions of the world, and specific local requirements and restrictions.
In general, multi-boat competitions are organized in a series of rounds, with the fastest boats in each heat qualifying for the next round. The losing boats from each heat may be given a second chance to qualify through a repechage. The World Rowing Championships offers multi-lane racing in heats, finals and repechages. At Henley Royal Regatta two crews compete side by side in each round, in a straightforward knock-out format, with no repechages.
In sweep or sweep-oar rowing, each rower has one oar, held with both hands. This is generally done in pairs, fours, and eights. In some regions of the world, each rower in a sweep boat is referred to either as port or starboard, depending on which side of the boat the rower's oar extends to. In other regions, the port side is referred to as stroke side, and the starboard side as bow side; this applies even if the stroke oarsman is rowing on bow side and/or the bow oarsman on stroke side.