Fatigue test results of the steel containing macroscopic inclusions under many-fold multiple load in two stress levels are presented. The test material is 3%Cr-0.5%Mo alloy steel commonly used for marine turbine rotor shaft. Fatigue tests of large number of cycles up to 108 were conducted. The primary stresses chosen are 1.2σw and 1.5σw, in which σw is the endurance limit under the constant load amplitude. The test results indicated that the life of the material containing many macroscopic inclusions of 0.3-0.9 mm in length might be predicted conservatively if the linear damage law would be used, because the value of Σ (n/N) was larger than 1 even when the primary stress was 1.5σw.
To clarify the large stern tube bearing performances under the static and dynamic load, the experimental studies have been carried out using a 1, 200 mmφ bearing test stand. This paper describes the results of the starting test. Some noteworthy results of the test are as follows: (1) The static friction coefficient increases as rest of the shaft becomes long. Especially, the higher the temperature of the bearing metal is and the lower the degree of the partial loading to the aft end of the stern tube bearing is, the larger the static friction coefficient is. (2) Even if the shaft rests for a long time, the high oil film pressure which has been generated before rest of the shaft is sustained partially during rest. (3) The occurrence of the stick-slip depends on the degree of a partial loading to the aft end of the bearing and the operating condition of the bearing.
In the shipping industry, it is a serious subject to keep their fleet in good order at the least expenses of maintenance. To solve this problem, the introduction of Productive Maintenance-not preventive maintenance-can be a decisive answer. When productive maintenance is applied to the ships, first of all, methods on compiling and handling of data about failure, repair, maintenance must be established. As a quick and convenient method for this purpose, the authors developed a system in the field of marine engines. The outline of this system is as follows; For the compilation of data, ..... Specially designed mark cards. For the handling of cards, (information retrieval, classification & etc.) ..... The card selector. The effectiveness of this system has been confirmed in the 60 ships, and the system is now producing good and useful results since it was started.
This paper reports on the principles, test and actual results of an automatic pressure-regulating type stern tube lubricating oil (L.O.) system which has been newly developed based on the idea to utilize the air-lock phenomenon sometimes observed in the piping. The system controls the L.O. pressure of the stern tube bearing, while keeping the differential pressure constant between the stern tube L.O. and sea water by controlling the air pressure of this system.