With the smaller boats, specialist versions of the shells for sculling can be made lighter. The riggers in sculling apply the forces symmetrically to each side of the boat, whereas in sweep oared racing these forces are staggered alternately along the boat. The sweep oared boat has to be stiffer to handle these unmatched forces, so consequently requires more bracing and is usually heavier – a pair (2-) is usually a more robust boat than a double scull (2x) for example, and being heavier is also slower when used as a double scull. In theory this could also apply to the 4x and 8x, but most rowing clubs cannot afford to have a dedicated large hull which might be rarely used and instead generally opt for versatility in their fleet by using stronger shells which can be rigged for either sweep rowing or sculling. The symmetrical forces also make sculling more efficient than rowing: the double scull is faster than the coxless pair, and the quadruple scull is faster than the coxless four.
Water machines are generally quieter than air rowers - you can still hear the water moving in the tank, but users tend to find this a pleasant ambient noise. Water rowers also tend to require little maintenance. Because there's a tank full of water involved, however, these can be very heavy, and larger than most other rowers: if you have a smaller home, a less-than-permanent workout space, or you move frequently, these might not be best for you. And because they're so high-performing, they do come at a high cost.
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 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.
Water rowers feature a tank that is actually filled with water as a means for resistance. As you increase the pace of rowing, the resistance naturally increases as well. This means that you can set your own pace and resistance in a single motion. The same is true for air rowers. Air rowers use a fan or flywheel to create resistance, and you have control over the intensity of the workout due to the fact that the air resistance depends on your pace. Most water and air rowers come equipped with -- or at least have as an option -- monitors that track various functions such as distance, strokes, strokes per minute and calories burned.