Abstract: An apparatus (15) mounted to a boat structure (17) for skimming a layer (65) of oil in an oil slick (26) deposited on water (29) and by which the boat structure (17) freely sinks or rises during such skimming regardless of the weight of accumulated oil (71) that is reclaimed and recovered in or removed from its hold (67). A drum (23) with a plastic liner (25) having an adherence characteristic for oil is supported on its axle(s) (29) that is rotatable by means of a pulley belt system (41) and motor (55). Two (2) slots (31, 32) in inner panels (18, 19) for compartments (35, 36) in which the pivotable arms (37, 38) are disposed provide for connection between the drum's axle(s) (29) with the arms (37, 38). A structural arrangement (60) secured to each of the pivot arms (37, 38) extends across the compartmental structures (21, 22) and into the boat structure (17) and to which a skimming blade (64) is secured and placed in cooperative relation with the plastic liner (25) to skim oil from its slick (26).