Eskimo skin boats possess remarkable advantages for their employment and conditions of use. Their hulls are light in weight, simple to build, and relatively easy to repair, yet they are highly shock resistant. They can carry large loads, yet are fast, they are capable of being propelled by more than one means, and they are exceptionally seaworthy. Floating ice is considered a major hazard to craft of all sizes, but the umiak, for example, can resist the shocks of ramming the ice to a degree beyond the tensile strength of the skin covering, by reason of the method of attaching the skin cover to the framework of the hull, and to some extent the form of the boat itself. The skin cover of the umiak is not rigidly attached to the frame in a number of places, but rather is a complete unit secured only at the gunwales and to the heads of stem and stern. This permits the skin cover to be greatly distorted by a blow, so that the elasticity of the material at point of impact is assisted by the movement of the whole skin cover on the frame. Also, the frame itself is flexible and allows distortion and recovery not only within the limits of the elasticity of the wooden frame but also by the movement of the lashed joints in the transverse frames. Some kayaks have similar characteristics, though their small size and the light weight of both boat and loading make its resistance to shock of far less importance than that of the umiak. Light weight is a highly desirable characteristic for small craft in the Arctic, since it permits the boat without the aid of skids or other mechanical contrivances to be removed from the water and carried over obstructions, and to be transported either by sledge or by manual portage over long distances. Lightness is obtained in the Eskimo skin boats by the small number and small size of the wooden structural members used in their construction. The resulting light weight hull permits heavy loading in proportion to the size of the boat, and it allows building with a minimum of material, in a country where such materials as wood are scarce and hard to obtain. For all small craft in Arctic waters, where distances between sources of supply may be great and the time that the water is open to navigation is relatively short, speed is an important and desirable attribute that permits movement with a minimum of effort. The exigencies of Arctic travel make it further desirable that small craft be capable of propulsion under paddle, oars, sail, or low-powered gasoline motors. The umiak, because of its form and weight, can be modified to meet this requirement without loss of other desirable attributes, and to a slightly lesser degree, the same may be said of the kayak.