Abstract: A barrier for containing oil spills or other debris on the surface of a body of water includes buoyant sections connected by a sliding seal for allowing sliding relative vertical motion and limited relative angular movement between the sections to accommodate extreme and abrupt variations in water surface level and turbulence resulting from wave action. The seal connection is made up of a vertical inner slide member, either integral with or attached to one end of one section, and a mating outer member integral with or attached to the opposite end of a similar section, the outer member having an undercut, open-ended slot for engaging the slide member with sufficient clearance to permit relative vertical sliding movement between the members while at the same time providing an effective seal between the sections.