Which mark indicates the best route also known as a safe waterway?

The safe water mark buoy is specifically designed to indicate a safe waterway or a clear channel. These buoys are often used to guide mariners through waters that could have hazards surrounding them. They are distinguished by their vertical stripes, typically red and white, and they signify that there is navigable water to be found in the area, with the intention of directing vessels safely through potentially treacherous regions.

In contrast, other types of buoys serve different purposes. Port hand buoys mark the left side of a channel when approaching from seaward, while starboard hand buoys mark the right side, helping to delineate the navigable area but not specifically indicating safe waterways. Cardinal buoys, on the other hand, provide information about the safest direction to navigate around a hazard, indicating where safe water lies in relation to the buoy but not defining a safe way in and of itself. Thus, the safe water mark buoy stands out as the clear indicator of a navigable route or safe waterway.