舶用推進軸系の防食法に関する檢討
1961 年 10 巻 7 号 p. 293-298
詳細
1961 年 10 巻 7 号 p. 293-298
Prevention of (erosion) corrosion on the propeller and it's shafting was examined with a stern model and discussed the results.
In the case of running ship, protecting current to propeller (white arrow in Fig. 1) is used to be checked, and stray current (black arrow) arises in stern tube at the same time.
To prevent these troubles, several methods were ascertained. The results were as follows:
1) It is favorable for both propeller and it's shafting to make sure the connection between the intermediate shaft and bearing by the ring and brush.
2) Painting on the inner side of stern tube (especially copper alloy parts in it) would decrease the stray current mentioned above.
3) Zinc anodes attached on the boss of propeller are effective, but the effect are insufficient to the vicinity of blade tip. However, this foible is diminished by the coating on the inner half of propeller.
4) In case that cathodic protection by external anode would be used for the ship, it is favorable to connect this anode to the shafting directly, and not to the ship's hull.
