Which maneuver should be used when a vessel is approaching a curve in a river?

Reducing speed and maintaining a proper lookout is crucial when approaching a curve in a river for several reasons. Approaching a curve can often limit visibility and reduce reaction time due to the potential for obstacles or other vessels to be hidden from view. By slowing down, the operator has more time to assess the situation, ensuring that they can navigate safely through the curve.

Keeping a proper lookout is equally important, as it helps in identifying any hazards that may be present in or around the bend, including obstacles in the water, other boats, or even swimmers. This attentiveness not only promotes safety for those on board but also for others utilizing the waterway.

In contrast, speeding up would reduce the operator's ability to react to unexpected situations. Abruptly stopping the vessel can create confusion and pose a danger to other vessels, as well as creating a risk of losing control. Changing direction without warning would also be unsafe, as it could surprise other boaters and lead to collisions. Thus, the chosen tactic of reducing speed while keeping a lookout is the safest and most effective strategy when approaching a curve in a river.