An analysis of possible assessment of hazards to ship shaft line, resulting from impulse load

This paper presents a proposal of identification of a degree of hazard to ship shaft line due to impulse load caused by underwater explosion. A theoretical analysis was made of influence of changes in co-axiality of shafts on second-kind critical velocities resulting from elastic deformations of hull structure in vicinity of shaft bearing foundations. Results are presented of pilotage tests of underwater explosion performed on training water area. A preliminary mathematical model of underwater explosion is given with taking into account mass of explosives and distance from the tested object. The drawn conclusions show a way of identification of hazard to shaft line by using spectral analysis and time - runs of vibration signals recorded at shaft bearings.