The safest way to approach another vessel is from abaft that vessel's beam, known as the?

The safest way to approach another vessel from abaft that vessel's beam is referred to as an astern approach. This method is advantageous because it allows the approaching vessel to have a clearer line of sight to the other vessel's path and any potential hazards. Approaching from this position minimizes the risk of collision since the majority of vessels have better visibility and maneuvering capability in the forward direction. By coming in from astern, the vessel can also take advantage of the other vessel's wake, providing additional stability and control during the approach.

The other approaches mentioned do not offer the same safety benefits. A bow approach presents a greater risk of collision because it places the approaching vessel directly in the forward path of the other vessel. Similarly, a beam approach involves coming alongside the vessel, which can complicate the navigation and introduce the risk of crossing paths at high speeds. Lastly, an end approach, while it might sound safe, can still lead to difficulties in maneuverability and control as the vessel approaches from the rear, potentially leading to unintended interactions. Thus, the astern approach is deemed the safest method for navigating in close proximity to another vessel.