A vessel must proceed at a safe speed.

• A. Always
• B. Never
• C. Only in restricted visibility
• D. Only in daylight

Answer: (D)

A safe speed is defined by the ability to take proper and effective action to avoid collision and to stop within the distance available, given the current conditions. This requirement is not limited to any single circumstance—it applies at all times. You adjust your speed based on factors like visibility, traffic density, how maneuverable your vessel is, stopping and turning distances, weather, sea state, currents, and the use of navigation and radar aids.

Because of that, you must maintain a safe speed whether it’s daylight or in restricted visibility. Slowing down in restricted visibility helps you detect and react to potential hazards in time, but you still must maintain a safe speed even in daylight. The other options imply limits to when safe speed must be maintained, which isn’t correct; safe speed is a constant standard you meet under all conditions.