As far as a Sail is Concerned, it Deserves Special Attention. Merani has a 28-meter liftable "sail", but is not a common one, it is Multifunctional. The sail's "standby mode" and First function is to be a Cover for the sundeck; in flight, when passing under a bridge or in case of bad weather. Thus, also drastically changing the exterior shape. The "sail" structure represents a arch-shaped helium filled rigid "blanket", covered with lightweight flexible solar panels. The "sail-cover" is a real intersection between sail yacht and airship worlds. The "cover" functions as tiny airship. The "takeoff" and "landing" are effectuated through intelligent roll-on/roll-off cable system, that automatically adjust the inclination angle of the sail up to 80 degrees, simultaneously exploiting as much as possible sun and wind energy. The system enables you to fix the "cover" practically in any height (that is, in depending on the installed cables length). The "cover" is attached by a power tether and cables, could host a suite of spotlights, cameras, multi-spectral sensors, sound systems, antennae, insect-animal repellent and more.