Which of the following actions is critical for preventing capsizing?

Securing all equipment and distributing weight evenly is essential for preventing capsizing because balance and stability are key factors in maintaining a boat's upright position. When weight is distributed unevenly, it can create an imbalance that makes the boat more susceptible to tipping over, especially in rough waters or during maneuvers. Properly secured equipment also helps minimize shifting, which can further compromise stability.

In contrast, riding with a full tank of gas might contribute to stability in certain situations, but it does not address the broader issue of weight distribution and secure stowage. Making sharp turns around obstacles can increase the risk of capsizing because abrupt changes in direction can lead to sudden shifts in weight. Lastly, while having experienced boaters onboard can enhance safety and handling, it does not directly influence the physical stability of the boat. Thus, securing equipment and evenly distributing weight is the most critical action for preventing capsizing.