A flexible vessel includes a restraint structure and a barrier structure. The restraint structure further includes a first portion, and a second substantially rounded end cap portion that is attached to the first portion. The restraint structure also includes an array of tendons. The barrier structure is positioned within the restraint structure. When the barrier contains a fluid, a portion of the load is carried by the restraint structure and another portion of the load is carried by the barrier structure. The flexible vessel is collapsible to occupy a first volume and distended to occupy a second volume. The flexible vessel is part of a system when used in various applications with respect to a craft.