A downhole-type wellbore notching tool comprising: a cylindrical drum with a fluid inlet configured to be connected to a downhole end of a fluid conduit, the cylindrical drum having an outer surface along which is the fluid inlet, the cylindrical drum having a center and an inner surface; a plurality of fluid nozzles fluidically connected to an interior of the cylindrical drum and positioned around an outer circumference of the cylindrical drum, each of the plurality of fluid nozzles positioned to direct fluid away from the cylindrical drum and towards a wall of a wellbore to form a notch at a specified notching angle; a rotatable collar positioned in the center of the cylindrical drum, the rotatable collar having an outer surface parallel to the inner surface of the cylindrical drum; and a plurality of sleeve plates positioned between the inner surface of the cylindrical drum and the outer surface of the rotatable collar, each of the plurality of sleeve plates defining a hole with a diameter smaller than a diameter of a corresponding ball dropped through the fluid conduit, the corresponding dropped ball sized to trigger a specified notching angle; wherein each of the plurality of sleeve plates is coupled to a respective gate across a respective fluid nozzle of the plurality of fluid nozzles, and wherein each of the plurality of sleeve plates is configured to i) hold the respective gate in a closed position, and when the corresponding dropped ball is received, and in response to a pressure build-up caused by the ball being seated on the sleeve plate, to ii) rotate around the rotatable collar to move the respective gate to an open position to direct fluid towards the respective fluid nozzle. a cylindrical drum with a fluid inlet configured to be connected to a downhole end of a fluid conduit, the cylindrical drum having an outer surface along which is the fluid inlet, the cylindrical drum having a center and an inner surface; a plurality of fluid nozzles fluidically connected to an interior of the cylindrical drum and positioned around an outer circumference of the cylindrical drum, each of the plurality of fluid nozzles positioned to direct fluid away from the cylindrical drum and towards a wall of a wellbore to form a notch at a specified notching angle; a rotatable collar positioned in the center of the cylindrical drum, the rotatable collar having an outer surface parallel to the inner surface of the cylindrical drum; and a plurality of sleeve plates positioned between the inner surface of the cylindrical drum and the outer surface of the rotatable collar, each of the plurality of sleeve plates defining a hole with a diameter smaller than a diameter of a corresponding ball dropped through the fluid conduit, the corresponding dropped ball sized to trigger a specified notching angle; wherein each of the plurality of sleeve plates is coupled to a respective gate across a respective fluid nozzle of the plurality of fluid nozzles, and wherein each of the plurality of sleeve plates is configured to i) hold the respective gate in a closed position, and when the corresponding dropped ball is received, and in response to a pressure build-up caused by the ball being seated on the sleeve plate, to ii) rotate around the rotatable collar to move the respective gate to an open position to direct fluid towards the respective fluid nozzle.