Final answer:
When approaching a US Navy vessel, you must slow down to a wake speed, which is typically around 100 yards or 300 feet.
Step-by-step explanation:
According to the US Navy regulations, when approaching a US Navy vessel, you must slow down to a wake speed. The specific distance that you must slow down to a wake speed may vary depending on the size and type of the vessel.
However, in general, a safe distance to slow down to a wake speed is considered to be around 100 yards or 300 feet.