Analysis of the technical performance of a ship in service
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School of Engineering |
Master's thesis
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Date
2010
Department
Major/Subject
Laivanrakennusoppi
Mcode
Kul-24
Degree programme
Language
en
Pages
88 s. + liitt. 14
Series
Abstract
Ships technical performance weakens over time as the hull and propeller roughness increases and hull fouling grows. Measuring how much the performance has suffered is difficult as there are many variables affecting to ships performance during normal operation such as waves, wind, shallow water and ships floating position. The aim of this work was by using ships normal sensor for measurements to find an analysis method for measuring the weakened performance. The goal is to do that by normalizing the actual measurements using the knowledge of external environmental and ship conditions and adding filtering for extreme, unessential data due to accelerations, movements and manoeuvres to the measurements to exclude unreasonable results. For being able to normalize the results the dynamic and static phenomenon such as interaction between ship and waves, aerodynamic resistance and theory of hull fouling affecting to the ships performance during normal operation was studied from the literature. The measurements for this analysis were done onboard VLCC using NAPA Log system for collecting the data from the sensors and sending the results ashore. The results were then processed using MS SQL database engine and NAPA hydrodynamic calculations. The results show that the performance indexing indicated weakened performance during the measurement period with good correlation to what the theories would have forecasted. That proves that by using described methods for normalization and filtering the measurements performance can be reliable indicated and this information can be utilized for several benchmarking purposes.Description
Supervisor
Matusiak, JerzyThesis advisor
Vihavainen, TommiKeywords
ship dynamics, hull fouling, statistics, filtering, normalizing, propulsion