Why must vessels navigate with extreme caution under certain conditions?

Navigating with extreme caution under certain conditions is crucial primarily to prevent collisions and ensure safe navigation. In situations where visibility is poor, such as fog, heavy rain, or night time, the risk of encountering other vessels increases significantly. In these circumstances, vessels must exercise heightened vigilance and adhere strictly to the International Regulations for Preventing Collisions at Sea (COLREGs), which outline the responsibilities and actions that vessels should take to avoid collisions.

Operating with caution allows mariners to anticipate potential hazards, react appropriately to unforeseen circumstances, and implement safe navigation practices, such as reducing speed, using sound signals, and keeping a proper lookout. This proactive approach helps safeguard not only the vessel and its crew but also other vessels and the marine environment, aligning with the fundamental purpose of the COLREGs to promote safe passage and prevent maritime accidents.

The other options, while they may reflect valid concerns in certain navigational contexts, do not capture the primary reason for exercising extreme caution in navigation. Resuming normal operations quickly, avoiding course alterations, and compliance with international law are important, but they do not directly emphasize the core issue of collision avoidance which is the primary focus of safe navigation under adverse conditions.