A method of reinforcing a composite preform comprising: determining a location of a first cooling hole and a second cooling hole in a plurality of plies; where the cooling hole is configured to transport a cooling gas; disposing a z-fiber in the plurality of plies at a location proximate to where the first cooling hole will be located; where the z-fiber enters the plurality of plies at either an upper surface or a lower surface; and where the z-fiber traverses a portion of the plurality of plies in the z-direction proximate to where the first cooling hole will be located; and traverses the plurality of plies in an x or y direction further away from the first cooling hole; where the z-direction is in the thickness direction of the plurality of plies and where the x and y-direction are perpendicular to the z-direction, characterised in that: the method comprises a first z-fiber and a second z-fiber; the first z-fiber enters the plurality of plies at the bottom, or alternatively at the top, and traverses the plurality of plies to emerge at the top, or respectively the bottom, proximate the point at which the first cooling hole will be drilled, and then traverses the upper surface, or respectively lower surface, in the x direction and then re-enters the plurality of plies to emerge at the bottom, or respectively top, and then traverses the lower surface, or respectively top surface, in the x direction of the plurality of plies; the second z-fiber enters the plurality of plies at the bottom, or alternatively at the top, and traverses the plurality of plies to emerge at the top, or respectively the bottom, proximate the point at which the first cooling hole will be drilled and then traverses the upper surface, or respectively lower surface, in the y direction, and then re-enters the plurality of plies to emerge at the bottom, or respectively top, an then traverses the lower surface, or respectively top surface, in the y direction of the plurality of plies; and the method further comprises drilling the cooling holes after introduction of the first and second z-fibers. determining a location of a first cooling hole and a second cooling hole in a plurality of plies; where the cooling hole is configured to transport a cooling gas; disposing a z-fiber in the plurality of plies at a location proximate to where the first cooling hole will be located; where the z-fiber enters the plurality of plies at either an upper surface or a lower surface; and where the z-fiber traverses a portion of the plurality of plies in the z-direction proximate to where the first cooling hole will be located; and traverses the plurality of plies in an x or y direction further away from the first cooling hole; where the z-direction is in the thickness direction of the plurality of plies and where the x and y-direction are perpendicular to the z-direction, characterised in that: the method comprises a first z-fiber and a second z-fiber; the first z-fiber enters the plurality of plies at the bottom, or alternatively at the top, and traverses the plurality of plies to emerge at the top, or respectively the bottom, proximate the point at which the first cooling hole will be drilled, and then traverses the upper surface, or respectively lower surface, in the x direction and then re-enters the plurality of plies to emerge at the bottom, or respectively top, and then traverses the lower surface, or respectively top surface, in the x direction of the plurality of plies; the second z-fiber enters the plurality of plies at the bottom, or alternatively at the top, and traverses the plurality of plies to emerge at the top, or respectively the bottom, proximate the point at which the first cooling hole will be drilled and then traverses the upper surface, or respectively lower surface, in the y direction, and then re-enters the plurality of plies to emerge at the bottom, or respectively top, an then traverses the lower surface, or respectively top surface, in the y direction of the plurality of plies; and the method further comprises drilling the cooling holes after introduction of the first and second z-fibers. the method comprises a first z-fiber and a second z-fiber; the first z-fiber enters the plurality of plies at the bottom, or alternatively at the top, and traverses the plurality of plies to emerge at the top, or respectively the bottom, proximate the point at which the first cooling hole will be drilled, and then traverses the upper surface, or respectively lower surface, in the x direction and then re-enters the plurality of plies to emerge at the bottom, or respectively top, and then traverses the lower surface, or respectively top surface, in the x direction of the plurality of plies; the second z-fiber enters the plurality of plies at the bottom, or alternatively at the top, and traverses the plurality of plies to emerge at the top, or respectively the bottom, proximate the point at which the first cooling hole will be drilled and then traverses the upper surface, or respectively lower surface, in the y direction, and then re-enters the plurality of plies to emerge at the bottom, or respectively top, an then traverses the lower surface, or respectively top surface, in the y direction of the plurality of plies; and the method further comprises drilling the cooling holes after introduction of the first and second z-fibers.