Class V (Expert). The closest most boaters get to a Class V rapid is a campfire story. Few commercial rafting trips will dare a rapid of this caliber—long, rock-strewn stretches of water boiling with treacherous currents, steep drops, waves like mountains. To negotiate a Class V rapid safely, a boater needs expert skills and time to scout it from shore. Once on the water, a boater must execute precise maneuvers with little room for error. There’s a high risk of injury or death for the unprepared. (Yahoo Factor: Very little; the roar of the rapid would drown out anything as feeble as a “Yahoo” anyway. The most appropriate response may be applause when the skilled boater is safely out of the boat and back on shore in one piece.)