I thought hiking where using your hands is necessary was class 3, and 4th class is where ropes and technical gear is pretty much necessary for most climbers.
...but I may be wrong.
Steve,
Maybe I'm wrong, but I always looked at it like anything that requires a rope and is technical to be class 5. Falls on a class 4 is likely fatal and you have to turn in to go down. Falls on a class 3 would be serious injury.
