This paper presents possible ways of identifying the operating states of naval gas turbines by the Base Diagnostic System (BDS) application. The system configuration, testing means and methods are demonstrated in this paper, whilst the application of methods of vibroacoustic analysis in naval technology is also discussed. BDS is used in ships that are powered by the COGAG power plant. This paper examines the permissible in-service imbalance and appropriate assembly of turbine rotors on the basis of selected vibroacoustic parameters, as well as the determination of their permissible operation time resources. Another element of BDS that will be analysed in this paper is the vibration control of misaligned propulsion shafts.

The following paper presents load analysis of propulsion engine during ship's speed acceleration. This process is carried out after manoeuvring in order to receive, as fast as possible, exploitation speeds of the ship, achieved during the voyage. The analysis concerns direct propulsion power system of low-speed engine of constant pitch propeller. Wrong steering process of engine load changes in temporary states, can cause engine overloading, as the result of its operation on the external limiting characteristic and can end up in engine seizure. Control of engine operation is carried on through selecting of adequate setting of rotational speed governor, which for specified external conditions can result in adequate position of fuel link and the choice of adequate fuel index arm dose. Equalization of the power delivered by the engine in given conditions of work with power required by the ship's propeller cooperating with the hull, will establish adequate rotational speed of the engine and finally the speed of the vessel. In order to speed up the sip's motion, there must occur an overflow of propeller thrust over the required thrust (resistance) and this, in turn, is connected with the necessity to ensure the engine power surplus over the power required for a given range of operation or in other words sailing speed. This article presents the working model of ship propelling system during speed acceleration and concerns mainly nonoverload running of the engine. The model described above has been verified during tests in real conditions at sea.

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The paper presents results of the experiment focused on evaluation of records of runs of the engine in good condition as a reference for subsequent detection of faults of fuel system of medium speed diesel engine. The aim of research was determination of limits of instantaneous angular speed's spread spotted between random starts of the engine, without any fault condition simulation. Due to fine variation of the load setup and different ambient condition, every record of angular speed of independent starting, despite of attempts to sustain the same load and rotational speed value, presents some deviations between runs. Having on mind utilization of such measurement as a template for further comparison, is crucial to find out how random changes of ambient conditions and accuracy of revolutionary speed setup affect the IAS magnitude course. The answer was got in way of registration of numerous runs of the test engine after independent starts and hand adjustment of required RPM's. The experiment was carried out at laboratory stand in GdyniaMaritimeUniversity, equipped with diesel engine Sulzer 3AL 25/30 driving electrogenerator. Sulzer 3AL 25/30 is three cylinder, medium speed, four stroke marine diesel engine, with maximum output 400 kW at 750 rpm. Independent records were treated as random variable and were compared each other. Obtained results were compared with differences between healthy engine and with simulated malfunctions of fuel injection.

Presently, as a result of the technical progress, more and more complicated machines are being used in our everyday life. This is especially the case in relation to technology used at sea, where highly specialised services are needed. Sophisticated marine devices require special diagnostic methods that take into account the specific conditions of use of this type of machinery. In this paper we present the diagnostic systems elaborated to support the exploitation of the vessel power plant with gas turbines. During engine assembly, the rotating components are mounted with great attention in order to minimise shaft unbalance. However, even while applying the highest standards, factors such as machines' imperfection or differential thermal expansion cause a small residual unbalance of the gas turbine rotor. The dynamic problems of Marine Gas Turbine Engines are directly related to such basic elements as rotors, bearings, struts of bearings, engine body and the type of substructure.