It has heretofore been proposed to provide elongated, inflatable pneumatic structures such as life rafts, boats, or toboggans, the structures having no frames of rigid material and usually having relatively soft, rounded top and bottom faces. Such devices are disclosed in U.S. Pat. No. 2,191,374 to Dixon of Feb. 20, 1940; U.S. Pat. No. 3,432,182 to Solipasso of Mar. 11, 1969, and U.S. Pat. No. 3,694,836 to Serra of Oct. 3, 1972. It has been found that inflatable mattress type devices are not practical for ice rescue craft in northern climates, for the reason that the rubber bottoms are rounded and do not spread the weight sufficiently. They tend to tear and deflate on sharp ice, tin cans, broken bottles and the like and the soft rubber tops permit prone adults to roll off especially if the device is yieldably supported in water.
Another line of buoyant floats or boats proposes to enclose an inflatable loop body in a frame of rigid material, the craft being wide enough to accomodate a sitting person. While probably stable in water, these boats occupy too much storage space, and present a soft, bottom face to ice and snow which precludes its rapid advance. In U.S. Pat. No. 1,884,705 to Hoffman of Oct. 25, 1932, and U.S. Pat. No. 1,927,124 to Jones of Sept. 19, 1933 the inflatable boat, or float, has a soft fabric bottom which might tear on sharp ice or on broken bottles, tin cans, etc. caught in ice.
Life saving apparatus of the non-inflatable type is disclosed in U.S. Pat. No. 2,050,138 to Walters of Aug. 4, 1936, the bouyant member having rope handles therearound but being triangular in cross section with one side down and the other two sides being inclined and incapable of supporting a prone adult. A parallelogram, and square, shaped body is also disclosed in this patent. Similarly a buoyant cruise board of rigid material is taught in U.S. Pat. Des. No. 157,564, Byerly of Mar. 7, 1950, the board tapering in depth and width from front to rear.
An elongated buoyant ice rescue craft, about 12 feet long, is disclosed in U.S. Pat. No. 3,532,066 to Clemans of Oct. 6, 1970, the top deck being cross-slatted, exposing the foam material at the ends and there being no provision for housing of the recovery lines or for compact storage of the craft.