Slide on Prop Protector for 25 mm shaft - 80 mm diameter blade.

25 mm BORE SLIDE-ON PROP PROTECTOR 80mm DIAMETER BLADE
 
Manufactured in one piece with a width of only 12mm (0.47"), it is designed for installations where the gap between the propeller and the shaft bearing is small. A gap of 18mm (0.7") is sufficient; this includes 6mm (1/4") of space for water to circulate to the shaft bearing. This type is available for shafts of 20mm (3/4") dia. up to 55mm (2 "). It simply slides onto the shaft after the propeller has been removed and is secured with a set screw that locates into a small drill dimple made in the shaft.