Lookout, safe speed and risk of collision

Seeing another boat is only part of lookout. Rule 5 requires a proper lookout at all times by sight, hearing and all available means appropriate to prevailing circumstances. Its purpose is full appraisal of the situation and collision risk. A screen can add information without turning what it misses into empty water. Proper relates the obligation to the environment; it does not allow observation to be abandoned because it becomes inconvenient or an electronic system appears reassuring. The rule addresses appraisal, not simply possession of a device.

Rule 6 relates speed to effective avoiding action and stopping within an appropriate distance. Factors include visibility, traffic density, stopping distance, turning ability, background lights, wind, sea, current and draught relative to available depth. Maximum engine speed and a posted harbour limit do not exhaust that assessment. Staying below a limit does not establish safe speed in prevailing conditions: the limit and Rule 6 can apply together. The rule supplies relevant factors, rather than a universal speed for every recreational hull.