The tent is supported by two parallel, semi-circular arches with a radius of 1.25 m, consisting of 10 screwed elements of glass fibre tubes of 10 mm in dia., spaced by 2 mm. It is first held by two adjustable tensile ropes. Then four ropes are used for holding the tent on the arches at a spacing of 0.75 m and at an angle of 45 deg.. The semi-cylinder is 2.5 m wide, 2.0 m long, and 1.25 m long, and 1.25 m high. ADVANTAGE - Rapid erection and dismantling.