Which action is NOT permitted when navigating in restricted visibility?

When navigating in restricted visibility, proceeding at full speed without taking precautions is not permitted because it significantly increases the risk of collision. One of the key principles of safe navigation under the Navigation Rules is to ensure the safety of the vessel and its crew, which involves taking appropriate measures when visibility is limited. Full speed in such conditions reduces the ability to react to other vessels or obstacles and makes it harder to assess the situation accurately, ultimately compromising safety.

Navigating with radar, sounding appropriate signals, and reducing speed are all considered prudent actions in restricted visibility. Using radar allows a vessel operator to detect other vessels and obstacles that may not be visible to the naked eye, enhancing situational awareness. Sounding proper signals is crucial to alert nearby vessels of your presence, especially when visual contact is restricted. Reducing speed allows for more time to react to unforeseen circumstances, greatly increasing the chances of avoiding a collision. These actions align with the principles of safe navigation and are vital for maintaining safety in challenging conditions.