Which of the following is NOT listed as a factor in determining safe speed?

• A. Visibility
• B. Engine horsepower
• C. Weather conditions
• D. Proximity of navigational hazards

Answer: (B)

Safe speed is about what you must be able to do given the on-the-water conditions, not how powerful your engine is. The idea is to choose a speed that lets you take proper and effective action to avoid a collision. That means looking at visibility (how far you can see and what you can detect), weather and sea state (wind, waves, current) which affect stopping distance and handling, and the proximity of navigational hazards and other vessels (how close hazards are and how busy the area is). These factors directly influence how quickly you need to be able to maneuver or stop.

Engine horsepower, while it affects how fast or quickly a vessel can accelerate, does not reflect the current risk or the amount of distance you need to avoid hazards. Therefore it isn’t used to determine safe speed in the moment.