Abstract: The invention provides for a hydrocarbon skimmer (10) interconnected to the floating roof (30) of a floating roof storage tank (300) wherein a liquid mixture of sour water (40) and hydrocarbons (50) are stored. The hydrocarbon skimmer (10) of the present invention is placed in a formed cavity (100) located on the underside (20) of the floating roof (30) wherein the cavity (100) extends above the surface of the floating roof (30) and is capable of collecting the hydrocarbons (50) from the liquid mixture. A funnel (40) is attached to the underside (20) of the roof (30) in the cavity (100) to extend downwardly into the liquid mixture wherein the funnel (140) has formed perforations (500) near the attachment of the funnel (140) to the underside (20) of the roof (30). A float (110) is operatively connected to the funnel (140) and selectively closes over the perforations (500) when the float (110) is in sour water (40) and opens over the perforations when the float (110) is disposed in hydrocarbons (50).