How high must registration numbers be, as a minimum requirement?

The requirement for registration numbers to be at least three inches high is established to ensure they are easily readable from a distance when the vessel is on the water. This is crucial for law enforcement and other boaters to identify vessels for safety and regulatory purposes. If the numbers were smaller, they might not be visible enough in various conditions, such as from a distance or in poor visibility. Having registration numbers at a height of three inches strikes a balance between visibility and practicality, thereby aiding in the enforcement of boating laws and regulations.