This is a great question. Sailing is not the oldest American Sport. In fact, there are several "sports" or "competitive games" that Native Americans still regularly participate in today (e.g. Lacrosse) that are far older than competitive sailing. Early European sports imported by the first settlers would include Fencing and target shooting as well as Wrestling and boxing.
However, the Americas Cup Trophy is the oldest Trophy in sailing (1851), and many resources claim that it could quite possibly be the oldest perpetual trophy in any sport to date. Competitive sailing is a sport with a long history in the Americas. With any luck, it will last for hundreds perhaps thousands of years to come.
As with any other sport, if it is competitive sailing then to beat your opponents, in pleasure sailing then to enjoy yourself
Track and Feild & Wrestling
Baseball is the oldest of the major American teamsports
Lacrosse (oldest American Sport), Hockey (not really American, though)
La Cross is not a cross of any sport its the oldest North American sport ...
Yes, netball is a very competitive sport
sailing isn't an olympic sport its a regular stupid sport like football