TITLE:
Propulsion Shaft and Gearbox Failure in Marine Vessels: A Duration Model Analysis
AUTHORS:
D. E. Onwuegbuchunam, I. C. Ogwude, C. C. Igboanusi, K. O. Okeke, N. N. Azian
KEYWORDS:
Shaft and Gearbox Failure, Propulsion System, Hazard Rates, Survival Analysis, Service Boats
JOURNAL NAME:
Journal of Transportation Technologies,
Vol.10 No.4,
August
10,
2020
ABSTRACT: The
need to mitigate downtime in marine
vessels arising from propulsion system
failures has led ship operating companies to devote enormous resources for research based solutions. This paper applied
duration models to determine failure probabilities of shaft and gearbox systems
in service boats. Using dockyard’s event history data on boat repairs and maintenance, we applied Kaplan Meier
hazard and survival curves to analyse probability of failure of shaft and gearbox systems in supply, crew and tug boats. We found that
average time to shaft and gearbox failure was 8.33, 5.23 and 5.21 months for
tug, supply and crew boats respectively. The hazard plots however, showed that
supply boats had higher probability of failure than crew boats and then tug
boats in that order. Further analysis using Cox regression model showed that the boats’ shaft and gearbox system failures
were significantly affected by level of lubrication oil, stress corrosion
cracking and impacts on the propulsion
system’s components. The paper proposes that design of maintenance schedules for
service boats should take the following into consideration: 1) estimated survival limits or failure times of
propulsion system’s shaft and gearboxes, 2) significant risk factors that affect failure
mode of the propulsion system components.