When navigating on the water, it is important to consider safe speed. This is a term defined by Rule 6 of the COLREGs as "a speed at which a vessel can be brought to a stop within a distance appropriate to the prevailing circumstances."
While there are many factors that influence safe speed, a few of the most significant include weather conditions, visibility, and surrounding vessels. Visibility: Conditions such as fog, rain, and darkness can decrease visibility, making it difficult to gauge distances or identify hazards. This can lead to collisions, which are more common at higher speeds. It is therefore critical to reduce speed when conditions such as these arise.
Wind and sea conditions also affect safe speed, as heavy winds can cause choppy waters that increase difficulty in controlling the boat and in maintaining a stable course. Sea conditions also influence speed, as rough waters may cause discomfort for passengers and require reduced speeds to ensure passenger safety.
Traffic density is another factor that needs to be considered when determining safe speed. High traffic density can create a high risk of collisions, which requires operators to navigate at lower speeds to maintain safety. Also, when approaching bridges, the height and width of the clearance should be taken into consideration to ensure that the vessel can safely pass through or under the structure. Finally, the draft of the vessel in relation to the available depth of water must be considered, as if there is little under-keel clearance, a grounding can be very damaging.