Borrowed from the KCSBC website...

IntroductionTypes of competitionBoat ClassificationBoat PlansFood for RowingBlade ColoursGlossary

There are two basic types of competition in which rowers take part. These are:

At these events the boats go down the course one after the other at 10-15 second intervals. Each boat has a flying start and is timed between the start line and the finish line. When all the boats have finished, the time for each to have completed the course is calculated, and a winner of each class is found.

These involve side-by-side racing and are usually more exciting to watch, apart from it being easier to get an appreciation of who is winning! Most river regatta courses have space only for two or, at most, three racing lanes and often have bends and other obstacles that require staggered starts and/or finishes.  These hazards provide ample opportunities for boats to interfere with each other and the Umpire (who chases each race in a launch) to make decisions that are a source of lively controversy for weeks.

Regattas on artificial courses (reservoirs or even purpose built international standard courses) usually have room for 6 lane racing. Regattas involve heats, semi-finals and finals held over the course of a day. Losing crews in the earlier rounds may get another chance to advance to the next round in an extra race known as a "Repecharge".