MARINE PROPELLER JPROP Use And Maintenance Handbook page 23

Section 8 - MAINTENANCE
The "JPROP" propeller needs very little maintenance.
Periodic maintenance, as described below, however will help
you achieve best performance, both in efficiency as well as
durability.
Regular maintenance
Periodically replay the zinc anode in order to avoid damage
due to corrosion.
1 - Remove the old anode ( Allen key type "B" - table 3).
2 - linstall the new anode taking care that the projection on the
anode fits the cavity in the bronze ring.
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