Mejora de la eficiencia en la compensación de agujas náuticas

The objective of this thesis is to improve the efficiency in the compass adjustment. First, a complete, orderly, synthetic and updated study on this matter is performed, including the state of the art, as well as the international and Spanish regulations, and then, four cases of study are considered to be focused on: i) Obtaining a method that allows to use the information of course over ground given by the GPS, in order to create the table of the residual deviations (deviation table) in small crafts, where the unique course indicator is the magnetic compass, once the deviations have been compensated to two leading lines close to cardinal magnetic courses separated by 90º. ii) A study on the incidence of asymmetric rods d, b (which cause coefficients A, E), in order to simplify the methodology to compensate. Besides, an improvement in the accuracy of the calculation of the residual deviations is also proposed when it is compensated by following lines that do not exactly coincide with cardinal or quadrantal magnetic courses. iii) A study of the problem in the selection of the quadrantal course for creating the deviation table by the practical formula of the equation of deviation, as experience demonstrates that, from the four deviations on the quadrantal courses, there is always one that is misaligned, i.e. that gives a coefficient D different from the obtained with any of the other three. iv) Obtaining a method for adjusting and creating the deviation table with a single swing to four magnetic courses. This saves time and fuel, as well as increases the safety of ships by staying less time near the shore and other vessels. Formally, the thesis is structured in four parts. The first one is introductory, and deals on magnetism, magnetic compasses, and systems of electromagnetic units. The second part corresponds to an updated study on the fundamentals of the compass adjustment. In the third part, the state of the art in regard to research on magnetic compasses and their adjustment is described. And in the fourth part, the aforementioned cases of study are developed. Finally, conclusions are drawn. In addition, an annex with the international and Spanish regulations on magnetic compasses and their adjustment is incorporated.El objetivo de esta tesis es mejorar la eficiencia en la compensación de agujas náuticas. En primer lugar, se realiza un estudio completo, ordenado, sintético y actualizado de esta materia, incluyendo el estado de la técnica, así como la normativa internacional y nacional, y a continuación, se plantean cuatro casos de estudio enfocados a: i) La obtención de un método que permite aprovechar la información de rumbo efectivo dada por el GPS, a fin de confeccionar la tablilla de los desvíos residuales en embarcaciones menores, cuyo único indicador de rumbo es el compás magnético, una vez se han compensado los desvíos a dos enfilaciones próximas a rumbos magnéticos cardinales separados 90º. ii) Un estudio sobre la incidencia de las varillas asimétricas d, b (causantes de los coeficientes A, E), a fin de simplificar la metodología para compensar. Aparte, también se propone una mejora en la exactitud del cálculo de los desvíos residuales cuando se compensa siguiendo enfilaciones que no coinciden exactamente con rumbos magnéticos cardinales o cuadrantales. iii) El estudio de la problemática en la selección del rumbo cuadrantal para confeccionar la tablilla de los desvíos residuales mediante la fórmula práctica de la ecuación del desvío, ya que la experiencia muestra que, de los cuatro desvíos a los rumbos cuadrantales, siempre hay uno que se desajusta; esto es: que da un coeficiente D diferente del que se obtiene con cualquiera de los otros tres. iv) La obtención de un método para compensar y levantar la tablilla de los desvíos residuales con un solo borneo a cuatro rumbos magnéticos. Esto supone un ahorro de tiempo y combustible, así como un aumento de la seguridad de los buques, al estar menos tiempo borneando cerca de tierra y de otros buques. Formalmente, la tesis se estructura en cuatro partes. La primera de ellas es introductoria, y trata sobre magnetismo, agujas magnéticas y sistemas de unidades electromagnéticas. La segunda parte corresponde a un estudio actualizado sobre los fundamentos de la compensación de agujas náuticas. En la tercera parte, se describe el estado de la técnica en lo referente a la investigación sobre compases magnéticos y su compensación. Y en la cuarta parte, se desarrollan los casos de estudio citados. Finalmente, se extraen las conclusiones. Además, se incorpora un anexo con la normativa internacional y nacional sobre compases magnéticos y su compensación.Postprint (published version

Analysis of vessel induced erosion through manoeuvre simulation and AIS data

This manuscript presents an erosion induced by manoeuvring ships assessment methodology in harbour basins with low bed clearance conditions. From the evolution of the bottom morphology, obtained from bathymetric surveys performed by the Port Authority, AIS data is used to analyse the traffic patterns in the basin and to relate the particular ships manoeuvres with the bottom morphology evolution. This allows for the detection of ships causing higher erosion in the basin. The manoeuvre simulator yields the use of the engines and thrusters during the in-port manoeuvres. Afterwards, literature equations are used to perform a stability assessment of the bottom material allowing to compute the required size for a rock protection layer in the basin.Peer Reviewe

Simulation-based model course to demonstrate seafarers' competence for deck officers' discipline

Postprint (published version

Compass adjustment by gps and two leading lines

The deviation card of a magnetic compass previously adjusted on two leading lines was created using a GPS receiver.During compass adjustment, the vessel follows magnetic courses using a gyroscopic compass and taking into account magnetic declination and gyro error. A satellite compass may also be used for the same purpose. However, some vessels are equipped with neither gyroscopic nor satellite compass. In these cases, a minimum of five leading lines must be considered, or a minimum of five bearings of conspicuous and distant points or sun’s azimuths must be taken. This renders adjustment and creation of the deviation card more laborious and time consuming. In order to expedite this process, a reliable and practical method was developed to create the deviation card with courses over ground given by a GPS receiver instead of the headings provided by a gyroscopic or satellite compass. For this purpose, the stream factor, which, as in the ECDIS, also includes other factors such as wind and waves, was considered. The method is valid for all vessels, but is primarily intended for ships equipped with only magnetic compasses to indicate the heading. Actual compass adjustment is carried out following two leadings lines that coincide with or are close to magnetic cardinal courses separated by 90º. Subsequently, courses over ground are taken when the vessel follows the main (four cardinal and four quadrantal) compass headings to create the table of residual deviations

Alternative manoeuvres to reduce ship scour

Scouring and sedimentation effects on the seabed induced by ship propellers during ship manoeuvring near harbour structures affect both structure stability and ship manoeuvring capabilities. This contribution proposes solutions at an operational level using the automatic identification system (AIS) and a bridge simulator. Two new alternative manoeuvres were designed and tested on a bridge simulator to obtain expected maximum scour depth and the results were compared with that of real manoeuvres (i) using mooring lines, and (ii) with tug assistance. A total of 42 test scenarios combining several manoeuvres and meteorological conditions were reproduced. Results confirmed a clear reduction in erosion depth with the alternative manoeuvres, with total reduction when using the tugboat. The presented methodology can be very useful to port authorities to prevent the effects of ship erosion on harbour infrastructures.Projecte finançador : Simulación y Monitorización para pronóstico de la erosión en ámbitos portuarios :TRA2015- 70473RPostprint (author's final draft

Safeguarding board-edge processing machinery

SIGLEAvailable from British Library Document Supply Centre-DSC:4335.3219(no 27) / BLDSC - British Library Document Supply CentreGBUnited Kingdo