Submarines get composite rudder blades

Pilgrim hydraulic nuts and oil injection system have been specified for Britain?s fleet of S and I class nuclear attack submarines undergoing major upgrade work. The nuts will enable fast installation and removal of a new generation of composite rudder blades and hydroplanes, says Pilgrim. The new rudder required a new fixing technique to ensure securing of the rudder on a keyless morse taper shaft. The interface is internal to the rudder and to assemble the rudder to the shaft requires considerable load to generate the friction necessary to drive the blades under load. This cannot be readily generated using a conventional nut, says Pilgrim. The company?s hydraulic nut was chosen together with the Pilgrim oil injection system to set the rudder and hydroplane blades on the taper shafts. Also when the nut is reversed and pressurised simultaneously with oil injection to the taper interface it will remove the blades without damage, says Pilgrim.