Propeller and Shaft Zinc
- Action: To Do List item A0062 – Replace existing cutlass bearing housing zinc.
- Action: To Do List item A0063 – Ensure installation of proper zinc with bond path to propeller/shaft.
- Completed: 21 February 2017
- Cost: $76.38
The issue of dezincification of the propeller due to no zinc protection caused by the cutlass bearing rubber insert isolating the shaft from the cutlass bearing housing zinc had us stymied until we noticed "something missing" when we removed the propeller shaft to access the stuffing box hose. To remove the propeller shaft the stuffing box was opened up exposing the packing gland cavity, the hose clamps were removed, and the hose removed from both fitting ends. Next removed the lock wire from the propeller shaft transmission coupling set screws, remove the two set screws, and removed the four coupling mount bolts. The propeller shaft was moved aft to mount a puller on the 4 inch diameter coupling and remove it. The shaft was then pulled aft and removed with the propeller still mounted on the shaft.
The 1.25 inch propeller shaft measured 62 inches long and exhibited corrosion and wear at both the packing gland and cutlass bearing areas.
Used sandpaper and sanded the propeller shaft which removed the corrosion and other surface contaminations.
Removed the 2 inch long cotter pin from the propeller nut and the nut was removed without much effort. Using the same puller that was used to remove the transmission coupling, unsuccessfully attempted to remove the propeller. The additional use of a 5 pound sledge hammer with the puller freed the propeller from the shaft. Measurement of the shaft threads indicated the thread size as 7/8 inch with 9 threads per inch. The shaft cotter key measured 2.45 inch long by 0.30 inch wide by 0.234 inch high.
Closer inspection of the bronze propeller nut revealed that one of the six tangs used to secure the cotter pin was shorter, most likely broken off. While researching the internet, it was discovered that only one image of bronze propeller nuts matched the nut shape and six tangs exactly - it was a Bronze Propeller Nut With Zinc Anode Model D as found on BoatZincs.com website. However this also meant that a larger portion of the bronze nut had broken off at sometime in the past. A check of old logs of previous owners confirmed this - the Musiaks, who owned the boat from February 1996 through July 2001, spare parts log listed a "Propshaft Zinc - Size D". Additionally, an old picture of Indra from 2004 showed a propeller shaft zinc was installed. A propeller nut D with zinc anode (1-1/4"), two spare replacement zinc anodes, and three spare mount screws were ordered from BoatZincs.com website for a cost of $76.38. The To Do List item A0062 – Replace existing cutlass bearing housing zinc, was no longer needed and the zinc and bond wire were deleted.
Since the propeller shaft was removed, decided it would be beneficial to order and replace the cutlass bearing. To determine the length of the 2 inch outer diameter cutlass bearing, it was removed. Attempts to turn or pull the cutlass bearing out failed, so a chisel was use to cut it and remove it. The cutlass bearing measured 4 inches long, was made by Duramax Marine, and was the DORIS composite model for 1.25 inch shafts, 2 inch outer diameter, and was 4 inches long.
