How are boats divided into four classes?

Boats are divided into four classes primarily by their length because this classification system helps establish safety requirements, registration regulations, and operational guidelines that vary depending on the size of the vessel. Different lengths of boats may encounter different types of waters, require different amounts of power, and be susceptible to varying weather conditions, which makes understanding boat length critical for safe operation. This classification allows boaters to understand the limitations and responsibilities associated with their vessels based on size.

The other options, while they may influence certain aspects of boating, do not provide a universally recognized framework for classifying boats. Color, intended use, or age can vary greatly across different boats within the same class and do not effectively address safety standards or regulatory concerns as length does. Therefore, classifying boats by length is the most practical and widely accepted method.