Abstract: A fluid pressure roller jack consisting of a flexible inflatable and collapsible fluid-tight bag which is formed with inherent fold lines such that the bag is invariably folded along the fold lines adapted to be kept folded while it is being collapsed. In a collapsed position the roller jack is rectangular in configuration in a plane having cut off its corners, while in a fully inflated position the roller jack is a sausage-like body in the form of a cylinder having hemispherical ends. The several fluid pressure roller jacks serve to lift a heavy article as jacks by an inflation from collapsed position to inflated position and to transport the heavy article supported on the roller jacks as rollers.

Abstract: An oil fence having a directional control device consisting of rudder plates or wind receiver plates secured to vertical plates or skirts of the fence at an angle thereto, which are subjected to a force due to relative movement of water or wind to cause the fence to position at an angle relative to the direction of the movement of the water or wind, whereby when the oil fence is being tugged by a towing boat the oil fence line is positioned at an angle without being subjected to any bending moment or any other undue force so as to collect or recover pollutants, e.g., spilt oil effectively from water surface.