Operating Stresses On S. S. "michigan" Propeller

Author:  Brewer, G.A.
Source:  SESA, Vol. XXIX, No. 1
Doc ID:  1972027
Year of Publication:  1972
Abstract:  
The failure at sea of a number of merchantship propeller blades initiated a search program supported by the Maritime Administraion, the American Burear of Shipping, the American President Lines and the States Steamship Company. Although extensive theoretica work shas been carried out in the past, very little full scale experimental stress measurements have been obtained. Brewer Engineering Laboratories, inc. was retained by the speonsor ot attach and protect fifty stran gages on the test propeller at the locations chosen by Littleton Research and Engineering Company. The propeller strain gages were protected fro the severe enviroment by means of synthetic rubber and metallic overlays. The gage wiring was led down each blade and into a specially machined, hallow tailshaft through a water froof bulkhead. The SS Michigan went into dry dock at the Behtlehem Steel Shipyard at Terminal Island, CA on June 15, 1970. The propeller was removed and all strain gages checked for continuity and ground resistance. Forty-two of the original 50 strain gages were found to be intact. No sign of deterioration due to cavitation or electorlysis attack wxisted on the metallic overlays or spot welding. Wire chafing within the fairwater adapter cap accounted for the low ground resistance values observed at the end of the voyage to Hong Kong.