The sleek Zephyr is a larger version of the Diablo, or a diminishing tube version of the Williwaw 1.5. The tubes diminish in diameter from 21" in the straight side sections down to 16" in the bow and stern, and is also an advantage when you encounter those upstream canyon winds in the afternoon. At 15' long and 7' wide, this is a great size raft if your normal trips are overnight and your load is 3-4 people and gear. This boat belongs in the Voyageur Series of rafts which is designed for big water, carrying large loads and handling technical maneuvers in challenging situations. The diminishing tube design offers more interior capacity and makes it ideal for punching through huge waves and big holes. With an extended straight section, these rafts are suitable for larger frames for multi-day trips or extra space to make a serious fish slaying setup.