The boat crew is broken into three sections:
the front 6 which is the first six paddlers;
the engine room which is the middle eight paddlers;
and the back 6 which is last six paddlers.
Weight of the paddlers must be taken into consideration when setting up the boat. Any serious weight distribution problems will adversely affect how the boat tracks for steering.
The biggest paddlers are placed in the middle or engine room and lighter paddlers at the front and back sections.
The front six paddlers set the pace and should be reserved for paddlers with good long paddling strokes. The rest of the boat needs something visual to follow. The rest of the boat will have short choppy stroke if the front has short choppy strokes.
The middle eight or the “engine room” is usually reserved for the heavier, stronger paddlers. During the middle of the race the engine room dictates the pace. The stroke rate of the crew is usually determined by the engine room. The stroke rate is not too fast as long as the big engine room paddlers can twist and reach. Once the engine room paddlers start shortening up on their stroke, you know the pace is getting too fast.
The back six paddlers of the boat should have the strongest people in the boat. It is not uncommon for a novice crew to set-up the boat with weaker paddlers who get out of stroke. For an intermediate crew or an advanced crew this would be a missed opportunity. A series which is a sequence of more powerful strokes meant to advance the boat and is initiated by the back six paddlers and ripples to the front of the boat.
Side to side and front to back weight distribution must be taken into consideration when setting up the boat. The sweep must have the knowledge of how to move paddlers around to improve the balance of the boat. Having the boat off balance can seriously affect how the boat tracks.
The sweep is 100% responsible for the safety of the crew. The sweep has the best view of any obstructions on the water and must make the required commands to the crew to manoeuvre the boat. In race situations the sweep must also be able to read wind and be knowledgeable of how the boat reacts in certain conditions. It is not good enough that the sweep can just keep the boat straight, he or she must be able to bring the boat to the line in whatever wind conditions and make the manoeuvres or commands to hold the boat on the line.
[Adapted from http://www.dragon-boats.com/dbnet/Dragon_boat_training_recommendations.htm#1 (now unavailable) More information may be found at Wikipedia]