During a full tidal cycle, the beach profile is exposed to continuously changing hydrodynamical conditions. Consequently, the profile evolves constantly to adapt to these changes. The equilibrium condition on tidal beaches is defined in terms of the relative occurrence of swash, surf zone and shoaling processes. We have assumed that the tidal beach profile is in equilibrium when the net sediment transport along a tidal cycle is zero. In this model the contribution of swash is considered negligible. A simple and easy-to-apply equilibrium profile formulation is proposed. This model is based on the assumption that surf zone processes dominate the profile morphology wherever wave breaking occurs during the tidal cycle. The obtained equilibrium profile is valid from the high tide level to the breaker point at low tide level. The tidal influence on the profile morphology is the lengthening of the surf profile. The higher the tidal range, the longer the surf profile. The model was tested against field and laboratory data, showing reasonable predictions of measured beach profiles.

Most offshore wind farms are bottom-fixed at sites with less than 50 m of water depth. For deeper waters, floating platforms are economically viable and, for many countries that have steep continental shelves, this is the only option for developing offshore wind farms. If wind energy is being harvested far offshore in deep waters (more than 200 m depth and hundreds of km from the coast), one possible alternative is the use of Floating Production and Storage (FPS) sailing ships that navigate through the ocean using wind force and utilize part of the harvested wind power to produce and store fuel. These ships are called “energy ships”. The objective of this paper is to carry out a qualitative determination of the global marine areas suitable for the operation of energy ships. To that purpose, wind and wave ship operation ranges have been defined and global databases of wind and waves have been used to obtain statistics of operational parameters. From the global analysis carried out the most promising areas and seasons for energy ship operation have been identified and qualified in terms of the aforementioned operational parameters.

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ResumenSe describe la evolución de las técnicas de diseño de los diques rompeolas y de algunos equipos y técnicas constructivas que los han impulsado. Se analiza sobre todo la influencia de las investigaciones teóricas y de laboratorio, desde los estudios y procedimientos pioneros de Iribarren hace 80 años hasta la construcción de diques protegidos con mantos monocapa de las últimas décadas y la optimización económica de las huellas energéticas y del carbono para una construcción sostenible. Se analiza el desarrollo de nuevos conceptos, la invención de nuevas formas geométricas para las unidades del manto, el gran impacto de las observaciones basadas en los ensayos físicos a escala reducida y la importancia de los condicionantes logísticos, métodos y técnicas de cada época para explicar la evolución en la manera de diseñar y construir grandes diques en talud a lo largo del tiempo.Palabras clave | Diques rompeolas; diques en talud; manto principal; espaldón; estabilidad hidráulica; rebase. ABsTRACT This paper describes the evolution of design techniques applied to mound breakwaters as well as some key tools, equipment and construction techniques. The influence of the theoretical and laboratory research is analyzed in detail, from the pioneering research by Iribarren eighty years ago to the construction of single-layer armored breakwaters in recent decades. The economic optimization and the new embodied energy and carbon concepts associated to the construction of mound breakwaters are studied. New concepts as well as the invention of new armor units are examined as is their impact based on the observations from small-scale physical experiments and the relevance of the equipment and logistic constraints to explain the evolution of the way mound breakwaters have been designed and built over time.Key words | Mound breakwaters; armor units; crown wall; hydraulic stability; overtopping. InTRODuCCIÓnDesde la antigüedad, la navegación marítima y fluvial propició el desarrollo del comercio y el intercambio cultural de los diversos pueblos. Fenicios, griegos y romanos establecieron redes de navegación apoyadas en puertos que actuaban como nodos de conexión del transporte, el comercio y la cultura entre diferentes pueblos. Para asentar los puertos en la antigüedad se utilizaban los abrigos naturales de la costa, las ensenadas y sobre todo, los ríos navegables. Aunque no se solían construir grandes obras de abrigo por su elevado coste, en algunos casos como el puerto de Alejandría o el de Ostia en la desembocadura del Tiber, se construyeron diques de escollera para crear zonas abrigadas artificiales (cerca de Roma en el caso de Ostia). Los diques se construían lanzando