A method for manufacturing a blade for a propeller, which blade has a leading edge and a trailing edge, which blade comprises a conduit in the blade, and a plurality of holes through which the conduit communicates with the exterior of the blade, which conduit is, by means of a supply duct through the blade, arranged to be connected to a source of pressurized air, for suppressing a cavitation collapse process by blowing air, via the supply duct, the conduit, and the holes, the method comprising - forming the conduit in the blade, and - making the plurality of holes through which the conduit communicates with the exterior of the blade, - characterized by providing a blade blank having an edge part receiving surface extending along at least a major part of the leading edge of the blade to be manufactured, wherein forming a conduit comprises building up an edge part onto the edge part receiving surface by a wire-based additive manufacturing process, wherein the additive manufacturing process is adapted to form the conduit at least partly delimited by the edge part and extending along the leading edge of the blade to be manufactured, wherein the amount of material applied to the edge part by the additive manufacturing process is such that it results in that the distance from the edge receiving surface to the leading edge, of the blade to be manufactured, is less than twice and more than half the width of the edge part receiving surface between a pressure side and a suction side, connecting the leading and trailing edges. - forming the conduit in the blade, and - making the plurality of holes through which the conduit communicates with the exterior of the blade, - characterized by providing a blade blank having an edge part receiving surface extending along at least a major part of the leading edge of the blade to be manufactured, wherein forming a conduit comprises building up an edge part onto the edge part receiving surface by a wire-based additive manufacturing process, wherein the additive manufacturing process is adapted to form the conduit at least partly delimited by the edge part and extending along the leading edge of the blade to be manufactured, wherein the amount of material applied to the edge part by the additive manufacturing process is such that it results in that the distance from the edge receiving surface to the leading edge, of the blade to be manufactured, is less than twice and more than half the width of the edge part receiving surface between a pressure side and a suction side, connecting the leading and trailing edges. wherein forming a conduit comprises building up an edge part onto the edge part receiving surface by a wire-based additive manufacturing process, wherein the additive manufacturing process is adapted to form the conduit at least partly delimited by the edge part and extending along the leading edge of the blade to be manufactured, wherein the amount of material applied to the edge part by the additive manufacturing process is such that it results in that the distance from the edge receiving surface to the leading edge, of the blade to be manufactured, is less than twice and more than half the width of the edge part receiving surface between a pressure side and a suction side, connecting the leading and trailing edges.