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Authors
Advisor(s)
Abstract(s)
A presente tese, proposta pelo Instituto Hidrográfico (Marinha), teve como
objetivo dar início ao desenvolvimento de uma capacidade no campo da otimização de
derrotas dos navios que integram o dispositivo naval da Marinha Portuguesa, em função
das previsões meteo-oceanográficas previstas.
Este trabalho dividiu-se em três partes: a primeira focou a revisão do estado da
arte do roteamento meteorológico, com uma introdução histórica, uma apresentação dos
diferentes conceitos de roteamento existentes na literatura e uma exposição dos dois
modelos de roteamento mais frequentemente utilizados.
Da análise feita na primeira parte, chegou-se à conclusão que nenhum programa
de roteamento meteorológico é genérico, ou seja, alheio às características singulares de
cada navio (e aqui reforça-se que não é de um tipo de navios, mas sim de um navio em
particular). Desta forma, o algoritmo de otimização a desenvolver teve que focar um
objeto de estudo real, para desta forma ser parametrizado e validado. Foi então decidido
que esta tarefa iria incidir sobre o N.R.P. “Sagres”, um tal l-ship da Marinha Portuguesa
que funciona como navio-escola. A escolha de um veleiro como objeto de estudo teve
como principal razão o desafio que este traz, visto que um veleiro está totalmente
dependente das condições climatéricas paras se movimentar. A segunda fase deste trabalho foi então a parametrização do rendimento do N.R.P.
“Sagres” em função da marcação do vento verdadeiro. Esta parametrização foi feita
através da análise estatística de um conjunto alargado de registos efetuado a bordo,
quando o navio navegava exclusivamente à vela. Esta base de dados foi agrupada em
intervalos de marcações, para análise e obtenção de uma correlação entre a velocidade do
navio e o vento verdadeiro que se fez sentir. A partir desta correlação alcançaram-se os
diferentes coeficientes de rendimento para cada um dos intervalos de marcação. Este
objetivo foi alcançado com sucesso.
A terceira e última fase deste projeto foi a participação no desenvolvimento de um
primeiro esboço de algoritmo de roteamento meteorológico, o qual teve apenas em consideração, nesta fase, o fator predominante num veleiro: o vento. Este algoritmo foi
testado num cenário verosímil, focado num trânsito no NRP Sagres, entre a Ilha Terceira,
nos Açores, e Lisboa, em Portugal Continental. As derrotas otimizadas obtidas pelo
algoritmo foram também bastante satisfatórios.
Por fim, são sugeridas algumas linhas de ação possíveis para futuros trabalhos, as
quais passam tanto pela melhoria da parametrização feita para o N.R.P. “Sagres” como
para a melhoria do algoritmo de otimização, em desenvolvimento no Instituto
Hidrográfico.
The present dissertation, as per suggestion of the Portuguese Hydrographical Institute, sought to develop the Institute’s skills in the area of the optimal weather routing of the vessels which integrate the naval fleet of the Portuguese Navy, according to the expected meteorological-oceanographic estimations. Generally speaking, the work is composed of three sections. The first one offered a state of the art of weather routing, with an historical introduction to it; a presentation of the various notions of weather routing existent in the specialized literature and of the kinds of weather routing themselves; and – finally – an exposition of the two most commonly used weather routing systems. From the analysis undertook in the first section, it was concluded that no weather routing method can be generalized, i.e., applied regardless of the idiosyncrasies of each vessel – note, of each vessel and not of each type of vessels. Therefore, and in order to study efficiently the optimization algorithm that was to be produced, a study case had to be defined. The decision was made to use the N.R.P. “Sagres”, a tall -ship of the Portuguese Navy that operates as a school-vessel. Choosing a tall-ship as a study case was due to the particular challenges brought by it, as a sailing ship depends absolutely on weather conditions to navigate. The second phase of the present work consisted in measuring the performance of the N.R.P. “Sagres” based in real wind conditions. Unlike the usual analysis methods, based in polar curves, the one here offered followed the statistic observation of a data set, which was divided in several other intervals, according to the different true wind bearings of each observation. The data was therefore plotted in scattering graphics, from which was extracted a correlation line and, therefore, a coefficient of performance was possible to calculate to each bearing intervals. Theoretically, if one multiplies these coefficients for a wind speed, it would be possible to estimate the expected ship's velocity. This objective was successfully achieved. The third and last section of the project entailed the elaboration of a first draft for a weather routing algorithm, for which only the most relevant element for a sailing-ship’s navigation was considered: the wind. This algorithm was tested in a highly probable passage between Ilha Terceira, in Azores and Lisbon, in Portugal mainland. The results obtained using the algorithm were highly satisfactory. Lastly, some future lines of action for future works like this one are suggested, relating especially to the measuring of the N.R.P. “Sagres” and to the improving of the algorithm being developed in the Portuguese Hydrographical Institute
The present dissertation, as per suggestion of the Portuguese Hydrographical Institute, sought to develop the Institute’s skills in the area of the optimal weather routing of the vessels which integrate the naval fleet of the Portuguese Navy, according to the expected meteorological-oceanographic estimations. Generally speaking, the work is composed of three sections. The first one offered a state of the art of weather routing, with an historical introduction to it; a presentation of the various notions of weather routing existent in the specialized literature and of the kinds of weather routing themselves; and – finally – an exposition of the two most commonly used weather routing systems. From the analysis undertook in the first section, it was concluded that no weather routing method can be generalized, i.e., applied regardless of the idiosyncrasies of each vessel – note, of each vessel and not of each type of vessels. Therefore, and in order to study efficiently the optimization algorithm that was to be produced, a study case had to be defined. The decision was made to use the N.R.P. “Sagres”, a tall -ship of the Portuguese Navy that operates as a school-vessel. Choosing a tall-ship as a study case was due to the particular challenges brought by it, as a sailing ship depends absolutely on weather conditions to navigate. The second phase of the present work consisted in measuring the performance of the N.R.P. “Sagres” based in real wind conditions. Unlike the usual analysis methods, based in polar curves, the one here offered followed the statistic observation of a data set, which was divided in several other intervals, according to the different true wind bearings of each observation. The data was therefore plotted in scattering graphics, from which was extracted a correlation line and, therefore, a coefficient of performance was possible to calculate to each bearing intervals. Theoretically, if one multiplies these coefficients for a wind speed, it would be possible to estimate the expected ship's velocity. This objective was successfully achieved. The third and last section of the project entailed the elaboration of a first draft for a weather routing algorithm, for which only the most relevant element for a sailing-ship’s navigation was considered: the wind. This algorithm was tested in a highly probable passage between Ilha Terceira, in Azores and Lisbon, in Portugal mainland. The results obtained using the algorithm were highly satisfactory. Lastly, some future lines of action for future works like this one are suggested, relating especially to the measuring of the N.R.P. “Sagres” and to the improving of the algorithm being developed in the Portuguese Hydrographical Institute
Description
Keywords
Otimização de derrota, previsões METOC, curvas polares, curvas de rendimento e N.R.P. “Sagres”. Weather route optimization, METOC forecasts, polar curves, performance curves and N.R.P. “Sagres”.