You are the watch officer on a power-driven vessel and notice a large sailing vessel approaching from astern. You should _____________.

In the scenario where a large sailing vessel is approaching from astern, maintaining your course and speed is the correct response. When there is a situation where a power-driven vessel encounters a sailing vessel approaching from behind, the sailing vessel has the right of way. By holding your course and speed, you are providing predictable navigation for both vessels.

This approach minimizes confusion and allows the sailing vessel to determine its best course of action in relation to your vessel. Changes in speed or course could lead to miscommunication and potential collisions, especially since the sailing vessel may already be making maneuvers to avoid you. Thus, maintaining course and speed demonstrates good seamanship in such circumstances, allowing the overtaking vessel to navigate around you safely.