The Society has initiated two research projects relating to marine propeller and propeller shaft assemblies. The first of these was Project M-8 Investigation of Tailshaft Failures, initiated in 1950. The second, an outgrowth of the first, was set up separately in 1953 as Project M-11, Investigation of Propeller Huh Sealing Arrangements. In the early phase of the work of panel M-8, the principal factors contributing to failures of tail shafts were assessed to include periodic stress reversal, stress variation, fretting corrosion, and corrosion due to ingress of seawater. Since the protection of the steel shaft within the propeller hub should be under the control of the designer and the installing agency, and since the possibility of the tail shaft "corrosion fatigue" can be minimized by attention to details, this aspect of the problem was considered to be of sufficient importance to pursue as a separate project. An interim report on this investigation was published in the SNAME Bulletin for July 1956.
The present and final report summarize the work and recommendations of the panel membership for Project M-11. This is endorsed by and offered to the industry by the Ships' Machinery Committee.