The first four boat classes I listed are called sweep. Each rower rows with one oar. The second four are sculls, where each rower rows with two oars. In the events that are not lightweight, that is the open events, there are no weight restrictions on the oarsmen. Their average weight is about 210 pounds.
Lightweights have to weigh-in between two hours and one hour before our race.
The open weight class boats are about 7 to 12 seconds than the equivalentlightweight boat. That is the double should be about 10 seconds faster than the lightweight double over 2000m. Sculling boats are about 15 seconds faster than a sweep boat with the same number of rowers. That is the double should be about 15 seconds faster than the pair. The spares are rowers who would replace another rower if they are injured or ill and cannot compete.