In a crossing situation, a power-driven vessel has a sailing vessel on its port side. What must the power-driven vessel do?

• A. Maintain course and speed, expecting the sailing vessel to give way
• B. Signal with whistle and alter course to port
• C. Keep clear
• D. Stop engines and drift to the side

Answer: (C)

In crossing situations, who must give way depends on which vessel is on which side relative to the other. When a sailing vessel is on the port (left) side of a power-driven vessel, the power-driven vessel is the one that must take early action to avoid and keep clear of the sailing vessel. The sailing vessel, being on the power-driven vessel’s port side, is effectively the give-way vessel in this scenario.

So the power-driven vessel should adjust to prevent a collision by keeping clear of the sailing vessel. This doesn't require stopping completely or drifting aimlessly; it means taking early, decisive action to avoid crossing paths, which could mean altering course away from the other vessel or reducing speed as needed to ensure safe separation.

The other options would either ignore the obligation to give way (maintaining course and speed under these circumstances) or introduce unnecessary or unsafe maneuvers (signaling and turning toward the other vessel, or simply stopping and drifting). The emphasis here is on avoiding the other vessel since it’s on the power-driven vessel’s port side.