Pilgrim Nut

1) it is to ensure a solid frictional drip between propeller and shaft, the use of pilgrim nut facilitates the transmission of engine torque without using key.

2) Pilgrim nut is basically a hydraulic jack with threads, screwed into slot provided on tail shaft. Propeller is forced onto tapered tail shaft region by using a steel ring, which receive the thrust from a hydraulically pressurized nitrile rubber tyre. 

3) The same process can be revered, by using additional withdrawal plate attached to the propeller by boss by studs, in order to take the propeller off the shaft. Hence when tyre is pressured the propeller come off the tapered region.

1) The pilgrim nut emploted for propeller mounting. Has a internal nitrile rubber tube which when inflated hydraulically, forces a steel loading ring against the hub

2) Outward movement of the ring from the flush position must not exceed one third of ring width, to avoid rupture of rubber tube 

3) Temperature of hub and shaft are recorded and also used to find correct final push up pressure provided in instruction book

4)Propeller is positioned and jacked on to the shaft taper before pilgrim nut is used to apply initial loading. A reference mark is made at this point about 25mm from forward end of hub.

5)nut is then turned until the loading ring is floshed ( venting hydraulic fluid) before full pressure is applied. 

6)during this stage, the dial gauge shows movement. A second 25mm mark from the forward face of the hub is then made. 

7)push up is registered by the distance between the 2 reference mark, is measured and noted.

8)nut is again vent and turned to bring loading ring to flush position and finally nipped up with tommy bar. 

9)The pilgrim nut can be reversed and used with a withdrawl plate and stud for removal of the propeller. 

10) to safeguard against any violent movement at release, wooden blocks are inserted as showm, and a gap of only a little more than the push up distance is left.

Assembly

1) Propeller is bedded to tailshaft and jacked up to usual shop mark 

2) Pilgrim nut then screwed on shaft with loading ring against prop boss 

3)With the Lever operated, high pressure grease gun, grease is pumped into the innet tube inside the nut at around 600bar ( working pressure stamped ) 

4)the propeller will be pushed sufficiently up to the taper to give required frictional grip 

5)the pressure is then release and nut is rotated until hard up against the aft face of the prop hub and loced, hair water cone then fitted

Removal 

1) After removal of fair water cone and locking plate, the pilgrim nut is removed, reversed and together with a loose shock ring is screwed back onto the shaft. 

2) A strong back is fitted and secured with studs to the propeller boss.

3)Grease is now inserted to the system expanding the inner tube foring the loading ring, strongback , withdrawal studs and prop aft. 

Advantages 

1)  Precise tightening working on measured applied load 

2) Adequate interference fit 

3) no heat used 

4) simple and safe to operate 

5) no shock loads applied 

6)considerable saving in man power and time

source: https://www.brighthubengineering.com/naval-architecture/47416-how-to-mount-a-propeller/