What should not be assumed when determining risk of collision based on radar information?

When determining the risk of collision based on radar information, it is crucial to understand that scanty information is not sufficient for safe navigation. Radar may provide useful data about surrounding vessels and their movements, but decisions should not be based on incomplete or limited information. Effective navigation requires comprehensive situational awareness, which includes interpreting data from radar in conjunction with other navigational aids and visual observations.

Assuming that scanty information can support safe navigation would lead to a failure in adequately assessing the risk and could result in dangerous situations at sea. Each piece of information gathered contributes to a fuller understanding of potential navigation threats, so relying solely on minimal or unclear data compromises safety and effective decision-making on the water. Hence, the emphasis is on the necessity of gathering complete and clear information for assessing collision risks accurately.