The viscous shear damper with a ringed rubber pasted on a surface of an inner mass so as to lie the rubber and silicon oil serially between the inner mass and the housing, was designed and manufactured as a trial in order to develop a viscous shear damper which was able to be adjusted the elastic effect. Then we investigated its elasticity effect by operating a V8 High Speed Diesel Engine with this damper and measuring the torsional vibration. We measured on conditions that the rubber hardness were 50 and 70 and working oil viscosities were various kinds. From this result, it was confirmed that we were possible to control the elasticity effect of damper, as we were able to change the equivalent complex damping coefficient of damper by pasting a ringed rubber on a surface of an inner mass.
In recent years, accompanied with the development of oil lubricating stern system, application of sea water lubricating system to the large/medium size vessels has been scarcely found. On the other hand, water lubricated rubber bearings are installed widely to medium/small size vessels in Japan, which navigate in the inland seas and the coast. This paper is the investigation report describing the experiences in rubber bearings installed to them, such as annual change of bearing clearance which shows the wear of bearing and shaft sleeve and the interval of replacement for various kinds of vessel which had been in service for longer than 4 years with the main engine power of over 3, 000 ps.
This paper describes a method to measure the instantaneous fluctuating shaft torque and its revolution speed while a ship in service. The signals, branched off the Digital Torsion Meter, are led to Transient Torque Meter PD-860. The data digitally computed in PD-860 is spectrally analyzed by means of FFT system. Judging from the results of actual measurements in servicing ships, this system was proved to be practically useful to observe the dinamic shafting characteristics.
The original instruction had been finalized and reported on the journal about thirteen years ago. At this time the revised one has been reported to meet the latest yard practice and new applicable insulation materials. Principal contents are as follows: (1) Instruction of sound & thermal insulation for each part of engine control room. (2) Insulation material and its heat transfer coefficient etc.