Abstract: An extendable nesting ski support structure as for supporting cargo including collapsed shelter devices for towing or pulling over ice, snow, and terrain. The skis are pivoted on brackets attached to the supported base and the brackets are atttached to the upper surface of flexible and resilient skis. By longitudinal shifting of the skis they are extendable and retractable as between sill supports beneath the supported base. The resilience and the flexibility improves the support system by providing shock absorption while in the extended position. A single lock serves both the extended and retracted skis, and on extension and locking, the skis are shaped by the flexural characteristics of the material of the ski.