The tactical experts will tell you how difficult the courses are for the sailing and rowing races. That is mainly due to the unique geography of the bay area, making it perfect to present Olympian challenges to the contestants.
David Dellenbaugh being a tactical adviser of the US team, stated that the currents and back eddies that are around the island at the mouth of the bay create challenges that are unique to those who race close to it. Again, the Sugarloaf Mountain and granite monoliths as well as the bridge nearby also create specific breeze and wind currents.
There are seven courses that have been designed for the Olympics. The focus is mainly on the Guanabara Bay area, but there are three race courses that have been designed to be in the open ocean. These lie off the Atlantic beach as well as close to the city of Niteroi.
Most classes would not be competing outside the bay area, but many would. Most tactical race advisors have realized that the venue in Rio offers great challenges for the sailing teams. With the two different race courses it is difficult to define the strategies to follow for the different races. For instance the races inside the bay would be driven by currents.
The waves in the bay are short and choppy (a bit like the water on your standard Croatian Kastela Bareboat Yacht Charter) while there is wind that comes in from the land. The race courses that cover the oceans include swelling of the ocean. The waves here are round and large with a steadier breeze. The currents out here are not as complicated as in the bay area. Rio sailing would demand varying experiences of sailing in the sailors and one who is a complete sailor would emerge victorious. Even the locals were not really at any real advantage in these waters.