Abstract: A marine propeller hub has an axial hole therein having a wavy, non-cylindrical surface consisting of a plurality of alternating peaks and valleys. A closely fitting resilient insert slips into the axial hub hole of the propeller hub and has an outer surface with peaks that extend into the respective valleys of the axial hub hole. The resilient insert has a cylindrical axial hole therein with a plurality of longitudinal keyways disposed in the surface of that hole. The keyways receive respective keys rigidly attached to the outer surface of a spline driver adaptor sleeve, the inner surface of which has keyways that receive the splines of a drive shaft of a marine motor. The resilient insert transfers torque from the driving shaft to the hub without slippage if the torque is less than a predetermined amount, and absorbs shock if the propeller strikes a rock or the like by allowing the peaks of the hub hole to compress the peaks of the resilient insert.

Abstract: A tube bulger for producing an enlarged ring-like bulge in the material around an end portion of a metal tube includes upper and lower die sections. When the upper and lower die sections are mated together, a cylindrical hole is formed. The end portion of the tube to be bulged extends into the hole. A ring-like, outwardly oriented enlargement of the cylindrical hole in the mated die sections forms a bulge cavity into which the bulge moves as it is being formed. An elongated mandrel extends through the opposite end of the cylindrical hole and into the open end of the tube. First and second sealing rings disposed about the mandrel on opposite sides of the bulge cavity prevent leakage of pressurized oil between the die and the mandrel. An oil conducting channel has an opening between the sealing rings.

Abstract: A tube bulger for producing an enlarged ring-like bulge in the material around an end portion of a metal tube includes upper and lower die sections. When the upper and lower die sections are mated together, a cylindrical hole is formed. The end portion of the tube to be bulged extends into the hole. A ring-like, outwardly oriented enlargement of the cylindrical hole in the mated die sections forms a bulge cavity into which the bulge moves as it is being formed. An elongated mandrel extends through the opposite end of the cylindrical hole and into the open end of the tube. First and second sealing rings disposed about the mandrel on opposite sides of the bulge cavity prevent leakage of pressurized oil between the die and the mandrel. An oil conducting channel has an opening between the sealing rings.

Abstract: A marine propeller includes a hub and a plurality of replaceable, respectively adjacently positioned blade support sections attached to the hub. The hub has a central portion and a plurality of spoke members that extend radially out from the central portion. Each of the blade support sections includes an inner lip that engages a respective one of the spoke members and an outer lip adjoining and overlapping the inner lip of an adjacent blade support section. Each pair of adjoining outer and inner lips are drawn tightly against a respective one of the spoke members by a plurality of screws. The spaces between the respective spoke members form a plurality of exhaust gas passages.