How do persons riding on the gunwale or decked-over bow affect the driver's performance?

Riding on the gunwale or a decked-over bow of a boat can significantly impact the driver's performance by decreasing both visibility and stability. When passengers are positioned on the edges of the boat, it can disrupt the balance and cause the boat to tilt or become less stable, particularly in choppy waters. This loss of stability can make it more difficult for the driver to maneuver the boat effectively, as a stable platform is crucial for maintaining control while navigating.

In addition to affecting stability, having passengers on the gunwales can obstruct the driver's line of sight, making it harder to see obstacles in the water, other vessels, or navigational markers. Good visibility is essential for safe boating operations, as it allows the driver to make timely decisions and react to changing conditions.

Overall, the correct answer highlights how these actions can create hazardous situations for both the passengers and the driver, making it essential for all individuals aboard to remain seated in designated areas while the boat is in motion.