In terms of crew training, the coxswain must ensure:

The emphasis on ensuring that all crew members are aware of safety protocols is fundamental for several critical reasons. First, safety protocols serve as essential guidelines that help prevent accidents and injuries while operating a vessel. When every crew member is knowledgeable about these protocols, it fosters a culture of safety that enhances overall operational effectiveness.

Additionally, comprehensive awareness of safety measures means that all individuals on board can respond appropriately in emergencies, which is crucial in high-stress situations where quick decision-making can save lives. This collective understanding also ensures that everyone knows their specific roles and responsibilities, thereby reducing confusion during emergencies.

The other options present scenarios that would undermine a safe and effective training environment. Senior crew members alone conducting training could lead to a lack of diverse perspectives and limit the effectiveness of training by not including all members' input or experiences. Optional training could result in some crew members being unprepared for critical situations, while the absence of daily drills could prevent crew members from maintaining proficiency and readiness, both of which are vital for operational safety.