Indigenous substitutes for "Lignum vitae" for making stern bearings for fishing boats

Difficulties are very often encountered in selecting proper material for making stern bearings for fishing boats. Conventional materials such as white metal, bronze etc. wear out too fast also causing considerable wear to the propeller shaft. Lignum-vitae, a natural wood commonly used for this purpose, is not available on a commercial scale in our country. Results of trials carried out to find out suitable substitutes for lignum-vitae from among indigenous timbers are presented in this paper.

A case history on the phenomenal corrosion of marine propellers in fishing boats

Although high tensile brassess of copper-zinc alloys (Manganese bronze) find extensive use in all marine applications, under aggressive sea-water, marine propellers cast out of such an alloy frequently suffer heavy corrosion damages due to dezincification. An interesting case history where a number of propellers have undergone dezincification in the Cochin backwaters is narrated in this paper.