Abstract: A floatable oil fence or boom for limiting the extent to which oil or other matter floating on a body of water can spread. The floatable boom includes an elongated tubular structure for containing air under pressure so as to be rendered floatable. An upper fin is fixed and extends longitudinally along the tubular structure, projecting upwardly therefrom to oppose the movement of water over the tubular structure. A lower fin is fixed to and extends longitudinally along the tubular structure, projecting downwardly therefrom to oppose the movement of the surface of a body of water and any material floating on the surface beneath the tubular structure.