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1 INTRODUCTION

Marine steam propulsion plants are very rarely

employed nowadays due to higher fuel consumption

of such systems compared with diesel motor engines.

Although the efficiency analysis of its main

components: main and auxiliary turbines [1] and

steam boilers [2] with steam air heaters [3] in the

open one turbine casing in each dry-dock for internal

inspection. Intermediate inspection of turbines is very

rare and is utilized only in the case of obvious

failures. In order to have better insight to failure

occurrence of marine steam propulsion turbine, LNG

2 STEAM PROPULSION PLANT

turbine is 24120 kW at 85.9 rpm

turbine will run for most of its service time.

stop valve 5.9 MPa and main condenser vacuum of

27°C. As both turbines are running at high speeds and

for cargo transport. Total running hours of the main propulsion turbine in the observed period of time were

63204 hours. The list of failures and influence of each mentioned failure of main turbine propulsion machinery

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pressure and low pressure turbines are given in

Table 1.

Both turbines are fixed above the main condenser.

The low pressure turbine shaft is passing through the

main condenser top and carries astern turbine which

freely rotates when main propulsion turbine is

Table 1. Main propulsion turbine characteristics [4]

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Turbine MCR NCR Critical Number

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High pressure 5888 5683 4320 Curtis wheel +

8 stages

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Table 2. The ship was built in 2001 and the first dry

was in 2006, and the third one in 2008. Accumulated

observed period were 63204 running hours.

4 FAILURE ANALYSIS

According to Table 2 all failures may be divided into

two main groups as critical and non-critical failures.

Critical failure has direct impact on capability of the

system to provide its output [6], i.e. failure which has