Complex sentence: The category of classes sailing yacht is among those officially recognized by the International Sailing Federation, includes within it the sailing boats that exceed 30 feet (over 9 meters), so in all respects similar to a yacht.
Split into simpler sentences: The category of classes sailing yacht is among those officially recognized by the International Sailing Federation. This category includes within it the sailing boats that exceed 30 feet (over 9 meters), so in all respects similar to a yacht.