Effect of the initial acceleration upon the wave resistance of ship models / by John V. Wehausen.

Mode of access: Internet.

Abstract of results published on a methodical series of resistance experiments on ship models,

Mode of access: Internet.

Model tests and numerical simulation of ship capsizing in following seas : final report for period December 1976 - October 1979 /

"Report no. CG-D-08-81."

A preliminary study of forces in ship moorings due to wave action /

Mode of access: Internet.

Ship mooring literature survey /

Mode of access: Internet.

Model study of ship mooring forces : ARD-12 /

Mode of access: Internet.

Model study of ship mooring forces : CVE-78 /

Mode of access: Internet.

A Gestão Documental na Autoridade Portuária de Barcelona

Este relatório de estágio representa o trabalho desenvolvido na Autoritat Portuària de Barcelona (APB), mais precisamente no Centro de Documentação da Autoridade Portuária de Barcelona, num período de 150 horas, onde tive a oportunidade de passar pelos diferentes serviços de documentação e realizar as tarefas inerentes a uma Instituição com idêntica tipologia àquela onde presto idêntica atividade em Portugal. Descreve-se a empresa e o trabalho desenvolvido no Centro de Documentação (CENDOC), considerando todas as funções desenvolvidas ao nível da gestão documental, na biblioteca, no arquivo intermédio, histórico e no arquivo fotográfico. O serviço de Arquivo agiliza a gestão de um fundo documental com mais de 3.900 metros lineares de documentos textuais, 500 metros lineares de documentação gráfica e cartográfica e 75.000 fotografias. Também gere o Património Cultural Móvel da APB, tanto o fundo documental do Arquivo Histórico (textual e imagens), como as coleções de objetos artísticos de interesse histórico e cultural (pinturas, esculturas, artes decorativas, cartas náuticas, modelos de navios). Toda a documentação do Arquivo Intermédio foi devidamente tratada, higienizada e organizada num novo espaço de arquivo, com melhores condições de acondicionamento. Aproveitando este trabalho, foi desenvolvido um novo Plano de Classificação em maio de 2012, no mesmo período que desenvolvi o estágio, a fim de melhorar o serviço de Arquivo. O serviço da Biblioteca tem ao alcance dos seus utilizadores um fundo de 1276 publicações periódicas e mais de 2.300 monografias, catalogadas no programa informático CDS/ISIS. A sua classificação é feita com base na Classificação Decimal Universal (CDU), e a partir de um tesauro especifico elaborado pelos técnicos do CENDOC. Enquanto Técnica Superior no Centro de Documentação e Informação na Administração do Porto de Lisboa (APL), o desenvolvimento deste estágio trouxe um importante contributo para o serviço que desempenho no Centro de Documentação e Informação na Administração do Porto de Lisboa. Este Estágio possibilitou, sem dúvida, um melhor conhecimento teórico e prático no âmbito das tarefas inerentes ao mesmo, e a capacitação para o desenvolvimento de projetos relacionados com as funções que desempenho, no Centro de Documentação e Informação da Administração do Porto de Lisboa.

Experimental investigation of the vertical forces acting on prolate spheroids in sinusoidal heave motion /

Mode of access: Internet.

Catalogue of the naval and marine engineering collection in the science division of the Victoria and Albert museum, South Kensington.

Mode of access: Internet.

Probabilistic models for the prediction of a ship performance in dynamic ice

We introduce two probabilistic, data-driven models that predict a ship's speed and the situations where a ship is probable to get stuck in ice based on the joint effect of ice features such as the thickness and concentration of level ice, ice ridges, rafted ice, moreover ice compression is considered. To develop the models to datasets were utilized. First, the data from the Automatic Identification System about the performance of a selected ship was used. Second, a numerical ice model HELMI, developed in the Finnish Meteorological Institute, provided information about the ice field. The relations between the ice conditions and ship movements were established using Bayesian learning algorithms. The case study presented in this paper considers a single and unassisted trip of an ice-strengthened bulk carrier between two Finnish ports in the presence of challenging ice conditions, which varied in time and space. The obtained results show good prediction power of the models. This means, on average 80% for predicting the ship's speed within specified bins, and above 90% for predicting cases where a ship may get stuck in ice. We expect this new approach to facilitate the safe and effective route selection problem for ice-covered waters where the ship performance is reflected in the objective function.

Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float

The North Atlantic spring bloom is one of the main events that lead to carbon export to the deep ocean and drive oceanic uptake of CO(2) from the atmosphere. Here we use a suite of physical, bio-optical and chemical measurements made during the 2008 spring bloom to optimize and compare three different models of biological carbon export. The observations are from a Lagrangian float that operated south of Iceland from early April to late June, and were calibrated with ship-based measurements. The simplest model is representative of typical NPZD models used for the North Atlantic, while the most complex model explicitly includes diatoms and the formation of fast sinking diatom aggregates and cysts under silicate limitation. We carried out a variational optimization and error analysis for the biological parameters of all three models, and compared their ability to replicate the observations. The observations were sufficient to constrain most phytoplankton-related model parameters to accuracies of better than 15 %. However, the lack of zooplankton observations leads to large uncertainties in model parameters for grazing. The simulated vertical carbon flux at 100 m depth is similar between models and agrees well with available observations, but at 600 m the simulated flux is larger by a factor of 2.5 to 4.5 for the model with diatom aggregation. While none of the models can be formally rejected based on their misfit with the available observations, the model that includes export by diatom aggregation has a statistically significant better fit to the observations and more accurately represents the mechanisms and timing of carbon export based on observations not included in the optimization. Thus models that accurately simulate the upper 100 m do not necessarily accurately simulate export to deeper depths.

Use of a scrapped ship as a floating breakwater for shore protection

The purpose of this research is to assess the effectiveness of a ship used as a detached floating breakwater for coastal protection and forming salients of sand or tombolos. Floating breakwaters have been extensively used as port or coastal protection structures and display advantages in terms of construction and ecology, amongst others. However, the greatest problem these structures present is the limited range of wave heights and periods for which they are really effective. Furthermore, ships may be considered as floating structures which, used as breakwaters, would keep the advantages of floating breakwaters and would increase their range of applicability. The possibility of using ships at the conclusion of their useful life for this purpose would also involve greater economic and environmental advantages. Tests were carried out to assess the ship’s effectiveness as a detached floating breakwater using a scaled down physical model to determine the vessel’s transmission coefficient (Kt) as to regular waves with significant periods of 5 sec to 12 sec and significant wave heights of 1.5 m to 4 m at depths from 20 m to 35 m. The ship proves effective for waves up to 4 m significant height and significant periods up to 9 sec. Hanson and Kraus and Pilarzyk’s analytical models, which take transmission coefficients into account, were used to analyse the shore’s response to the breakwater protection. The results obtained show that salients form for waves with periods between 6 sec and 9 sec. It is also concluded that the depths tested are far different from the more usual shallow water involved in constructing detached breakwaters and the shore’s response is therefore scarce.

Analysis of wave attenuation and shore protection of a bulk carrier ship performing as a detached floating breakwater

Análisis de la atenuación del oleaje por un carguero funcionando como dique flotante y aplicación a dos casos de protección portuaria y costera. The effectiveness of a bulk carrier working as a detached floating breakwater to protect a stretch of coast and form salients or tombolos is assessed in this paper. Experiments were conducted in the Madrid CEDEX facilities in a 30 m long, 3 m wide, 1/150 scale flume. The bulk carrier ship is 205 m long, 29 m wide and 18 m in height with a draught of 13 m, and has been subjected to irregular waves with significant heights from 2 m to 4 m and peak periods from 6 s to 12 s at a depth of 15 m, all prototype dimensions. Three probes were placed between the wave paddle and the ship to record incident and reflected waves and four probes were placed between the ship and the coastline to measure the transmitted waves. Transmission, reflection and dissipation coefficients (Ct, Cr, Cd) were calculated to determine wave attenuation. Results show good shelter in the lee of the ship with values of Ct under 0.5 for peak periods from 6 s to 11 s. In addition, forces on the mooring chains were measured showing maximum values of about 2000 tons at a 10 speak period. Finally, two analytical models were used to determine the shoreline’s response to the ship’s protection and to assess the possible forming of salients or tombolos. According to the results, salients - but not tombolos - are formed in all tests.

3D models created from ROV videos and their corresponding subtransect dimensions

Underwater video transects have become a common tool for quantitative analysis of the seafloor. However a major difficulty remains in the accurate determination of the area surveyed as underwater navigation can be unreliable and image scaling does not always compensate for distortions due to perspective and topography. Depending on the camera set-up and available instruments, different methods of surface measurement are applied, which make it difficult to compare data obtained by different vehicles. 3-D modelling of the seafloor based on 2-D video data and a reference scale can be used to compute subtransect dimensions. Focussing on the length of the subtransect, the data obtained from 3-D models created with the software PhotoModeler Scanner are compared with those determined from underwater acoustic positioning (ultra short baseline, USBL) and bottom tracking (Doppler velocity log, DVL). 3-D model building and scaling was successfully conducted on all three tested set-ups and the distortion of the reference scales due to substrate roughness was identified as the main source of imprecision. Acoustic positioning was generally inaccurate and bottom tracking unreliable on rough terrain. Subtransect lengths assessed with PhotoModeler were on average 20% longer than those derived from acoustic positioning due to the higher spatial resolution and the inclusion of slope. On a high relief wall bottom tracking and 3-D modelling yielded similar results. At present, 3-D modelling is the most powerful, albeit the most time-consuming, method for accurate determination of video subtransect dimensions.