The system of “water ratings” or “whitewater ratings” was designed so boaters and more appropriately, paddlers would know the difficulty of certain lakes, rivers and rapids. Here are some detailed descriptions of the system. Matching the whitewater ratings with the manufacturers recommendations for your hard shell, inflatable or folding kayak will ensure enjoyable paddling adventures.
Class A – Waters are calm and still, which is the case for most lakes and rivers.
Class I – These rapids are small and have slightly fast moving water. There are hardly any dangerous spots and those that are dangerous are easily spotted and avoidable. The risk to swimmers is small and can be corrected by self-rescue. In other words there is nothing to worry about in a Class I rapid.
Class II – With some basic training the obstacles in this class are easily maneuvered around or avoided. The swifter currents of water, channels, and rapids are easily noticed with some forward scouting. Swimmers will probably not get hurt in these rapids. It rarely occurs that someone may need outside assistance for rescue.
Class III – Accomplished whitewater skills and/or training are needed for these rapids. Constant changing rapids, harsh currents, large obstacle, and tight channels are prevalent. Larger rapids and currents can be seen but avoided. Risk to swimmers is still minimal and can be rescued by group or individually.
Class IV – These large and predictable currents require very strong boating skills. Some large waves, holes, and currents may be unavoidable. Quick thinking and fast skills are a must. Depending on water conditions the risk to swimmers can be high.
Class V – Expert only. These rapids put the boater into extreme danger. Large holes, rocks, waves, and currents are violent and all have an added danger. Rapids are longer and much more intense. Swimming is dangerous and not recommended.
Class VI – These rapids are unpredictable and may never have been run before. The only paddling here should be attempted by professionals under perfect conditions.