Original scientific paper
https://doi.org/10.21278/brod72306
ANALYSIS OF CORROSION DEPTH PERCENTAGE ON THE INNER BOTTOM PLATES OF AGING BULK CARRIERS WITH AN AIM TO OPTIMIZE CORROSION MARGIN
Špiro Ivošević
orcid.org/0000-0001-6670-4770
; University of Montenegro, Faculty of Maritime Studies Kotor, Put I Bokeljske brigade 44, Kotor, Montenegro
Nataša Kovač
orcid.org/0000-0002-6671-2938
; University of Donja Gorica, Faculty of Applied Sciences, Oktoih 1, Donja Gorica, Podgorica, Montenegro
Nikola Momčilović
orcid.org/0000-0001-5343-5129
; Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, Beograd, Serbia
Goran Vukelić
orcid.org/0000-0002-9472-9630
; University of Rijeka, Faculty of Maritime Studies, Studentska 2, Rijeka, Croatia
Abstract
To ensure the better structural integrity and maximum safety of bulk carriers in the ship design phase, an appropriate corrosion margin is introduced by the classification societies, which should enable the exploitation of ships during the projected 25-year life cycle. The new Common Structural Rules introduce even higher corrosion margin value to ensure the structural integrity of the ship. This directly affects the increase in hull weight and thus the need for more total installed power and higher fuel consumption. Higher fuel consumption results in increased emissions which directly affects environmental pollution. For these reasons, efforts are being made to introduce alternative energy sources, cleaner fuel, ship weight reduction, and the overall economic efficiency of ships. Therefore, using experimental data collected on aging bulk carriers, the paper explores the corrosion margin reduction potential considering its impact on hull weight. Assuming that the corrosive processes occur after four years of operation, a linear model that describes the percentage of plate wear as a function of the as build-in the thickness of inner bottom plates (IBP) of fuel oil tanks (FOT) located on the double bottom of aging bulk carriers, is analyzed. Over the course of 25 years, the IBP segment was monitored on 36 different ships surveys. In this way, 520 input data describing the depth of corrosion were formed. At the same time, records were kept on the mean thickness of the original metal plate, which enabled systematization of the empirical database and grouping of measured values by intervals of original plate thicknesses, and simple conversion of corrosion depth into adequate percentage values. Depth corrosion percentages were represented by standard linear models known in the literature. Based on this analysis, representative numerical and graphical results were obtained. Conclusions from the paper can assist to optimize corrosion margin and the energy efficiency of future vessels.
Keywords
ships corrosion; inner bottom plates; corrosion depth; linear model
Hrčak ID:
262595
URI
Publication date:
1.7.2021.
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