Authentic Yacht-Masters have a Rolex logo, engraved rehaut, and serial number. They also have a high-quality finish, and the second hand moves smoothly, not in a ticking motion.
Pull the crown out to the second notch and turn it clockwise to adjust the date.
The Rolex Yacht-Master features a programmable countdown with a mechanical memory that can be synchronized on the fly, a function tailored for the start of yacht races.