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The quick evolution of fish farming in Europe, and its development towards the open sea needs suitable farming tools. These tools must withstand the difficult sea states, but they must be easy to use, well adapted to the fish farming and not too much expensive. This book helps the design of such tools. It defines the solicitations of the sea on all the structures, and presents rules and methods to control these solicitations. Here, a structure is composed of a rearing support, a mooring system and equipments. This book describes these components, class them and gives lists of providers. The rearing support can be a cage, a group of cages or a boat. The support can float or to be submersible. The mooring system can be made up ropes, chains, anchors, concrete blocks, floats, clump weights... Equipments are all these tools as manual/automatic feeders, graders, aerators, sensors, fish pumps, net washers, antifouling, nets, net cleaners, counters, scales, work boats... In this book the environment of the fish farming structure is: -- the atmosphere, which takes into account the wind, the corrosion and the dissolved gases, -- the sea water, which is the main vehicle of solicitations, as wave and current forces, tide effects or corrosion, -- the sea bottom, where the structure is moored through the foundations of the mooring system., L'évolution rapide de la pisciculture marine en Europe et son extension vers le large nécessitent une adaptation des matériels d'élevage. Ils doivent résister aux difficiles conditions météo-océaniques tout en restant pratiques d'utilisation, adaptés aux conditions d'élevage des poissons et d'un coût d'achat et de fonctionnement limité. Le présent ouvrage aide à la conception de telles structures d'élevage. Il définit les sollicitations sur ces équipements et propose des régies et des méthodes pour contrôler leurs effets. Une structure se compose d'un support, d'un amarrage et d'équipements. L'ouvrage les décrit, les classe et propose également des listes de fournisseurs. Dans cet ouvrage l'environnement est représenté par : - l'atmosphère qui prend en compte le vent, la corrosion et les gaz dissous dans l'eau ; - l'eau de mer, vecteur principal des sollicitations, tels les efforts de houle ou de courant ou encore la corrosion ; - le fond, sur lequel est amarrée la structure.

The mechanical behaviour of sediments is usually studied from laboratory core analyses which do not take into account the real state of in-situ stresses. Therefore, the aimed purpose is presently to determine the in-situ geotechnical properties which mainly depend on the relationship between fine-grained particles and intergranular fluids. At IFREMER, these achievements have been pursued in the framework of 2 scientific program: "Nodules and Sedimentary Processes and Instability on Slopes, for which surficial measurements were conducted on selected seafloor targets usually pre-defined from high resolution geophysical data." 2 kinds of instrumentation were developed in correlation to 2 different strategies of handling at sea. There is the instrumentation of the submersible "Le Nautile" equipped with a vane shear device, which enabled us to measure for the 1st time the in-situ undrained shear strength of pelagic sediments in the nodule environment. The possibility of accurately choosing on the seafloor the testing sites by means of a submersible, enable us to achieve this spectacular operation of ground-truthing. The other set of instrumentation is an autonomous equipped frame tethered by a cable. It is a supported rig which can be handled by any customary oceanographic vessel and is designed to penetrate the seafloor up to 2 m with a piezo-cone.

On the bathyal slope for continental margins, steep and rocky substrates punctuated with cliffs and collapsing zones are frequently found. As survey and sampling with the classical technics from the sea surface is practically impossible in such an environment, in situ exploration with a submersible allows significant advances in ecology, with implications in paleoenvironment reconstruction. Mixing of material from shallow-water and deep-sea origins into bathyal sedimentation suggests that the so-called "fossil assemblages of outer platform" were frequently misinterpreted. Dense populations of animals closely related to fossil groups which were only considered as relict of the Past ("living fossils") and previously interpreted as shallow-water inhabitants during geological times can be discovered living in such bathyal communities. The role of bathyal ecological niches during global bioevents brings a new vision of the history of life in the Ocean through geological time and has to be further investigated. Examples from cruises monitoring the diving saucer Cyana (SP 3000) in the Bay of Biscay and off New Caledonia are given.

Responsible for large exchanges between the Ocean and the Lithosphere, oceanic hydrothermalism covers wide scientific domains, from the ocean chemistry to metallogeny. The exploration covers all scales, from the hydrothermal site to the Mid-oceanic ridge system. Modern bathymetry and imagery are required. Physical and chemical anomalies created in the ocean are used to detect and map its distribution. A specific effort in the field of ROV (Remote Operated Vehicle) is needed to acquire data at the corresponding working scale.

The basic principle of videogrammetry is the one used in photogrammetry systems, except that videogrammetry systems use video or digital cameras instead of photo cameras and that all the processing which is needed to obtain object coordinates from the images is performed in real time, without contact and with a high level of accuracy.

In remote control, the master element which the user operates looks for practical and historical reasons like the slave arm and therefore features a series architecture, with a few drawbacks in terms of mass, dimensions, rigidity and mechanical complexity. To remedy these defects, we are now introducing a new master element with parallel kinematics. This syntactor, derived from Steward's manipulators, has six degrees of freedom and comprises six motor-driven links arranged on a fixed plate (the base) and a moving plate on which a 6-axis force transducer and a handle are mounted. The device is made artificially free along a few or all axes by means of a hybrid position/force control software which translates the wrench of forces applied by the operator on the handle into displacement for the syntactor, as well as for the slave arm. The operator can thus control the syntactor and the slave arm on free moves, or forced moves, such as drilling, cutting. When the slave is also equipped with a 6-axis force transducer in its terminal part, the operational wrench of forces is then sent to the master in order to implement a two-direction remote control system with known modes, such as weight suppression, homothetic forces.

Detecting and localizing nuclear blasts was an essential stimulus of the actions undertaken in the 1960's to emplace seismological observatories on the seafloor. The plate-tectonic theory, in which the oceanic areas play a major role, greatly accelerated the evolution of modern oceanology. The contribution of Ifremer's department of Marine Geosciences, in helping to advance this area of research, has been significant since 1972. The need for refraction studies to explore the deep structure of the margins and ocean-continent transition zones led us to design a deep-sea Ocean Bottom Seismograph (OBS) MK I in 1975, rated to 6,000 metres depth. This system introduced, for the first time, the concept of "isolated seismic sensors". This principle was adopted later on by other instrument designers. The OBS MK II was constructed in 1978, namely to study interferences between the instrument and the "isolated seismic sensors" as well as to test, under real operating conditions, an instrumental design which makes use of the "long inverted pendulum" concept. A series of four instruments were built, which also incorporated some innovative features in OBS technology, such as high density digital recording. A new system, the Ocean Bottom Seismic System (OBSS), was designed in August 1990 aiming at the construction of a variety of instruments from basic modules.

The "CRABE" method is a crack detection technique based on the use of low electromagnetic frequencies. This (patented) method relies on a global injection of current within the structure under inspection. The presence of a crack shall cause a disruption in the current flow, and consequently of the magnetic field off the surface in the vicinity of a defect. It is this magnetic signature which is detected by the magnetic sensor used with "CRABE". The major advantage of this process, developed by TRAVOCEAN and the LETI Division of CEA with the help of IFREMER, appears clearly: No preliminary cleaning of the welds to be inspected is required, since no contact is necessary. Similarly, it shall be possible to inspect the whole of structures to a total cost all the more reduced than the detection equipment can be operated by means of a ROV (Remotely Operated Vehicle).

At present, offshore placers are generally exploited by means of traditional dredging equipment. This technique, called the "vertical method," consists of working the seabed directly from the surface support vessel through a rigid upflow pipe equipped, when necessary, with a sediment preloosening system. In contrast with the vertical method, this approach is based on the principle of working along the seabed with transfer of spoil up to the surface after extraction. We therefore call this the "horizontal method." Although it varies according to sites, in most cases this method comprises the design of a vehicle, self-propelled to some degree, which moves along the seafloor, carries and operates the appropriate mining tools and includes a system to transfer the collected spoil up to the surface for processing. This horizontal method is the approach choosen, studied and developped by offshore mining Group.

MORS ENVIRONNEMENT has developed for the University of Hawaii a new system, SI 4X1-3, for study of movement of tectonic plate. In a single unit are gathered an acoustic rangemeter, a data acquisition unit (for 8 external sensors), a long range telemetry, and a power pack for 6 to 10 years life. The surface unit is a standard 16 frequencies RM 201 "OCEANO INSTRUMENTS" rangemeter. The programmation, the data transmission control, and the exploitation of the measures are done with a compatible IBM/AT. This system includes the know-how of SUBER and OCEANO INSTRUMENTS, and finds today a very large application field: Control and command of instrumented closing pigs; Seawater quality control without buoys and transmission up to 8 km; Corrosion control on platform and pipeline; Control and command of BOP, Christmas tree of other underwater system; High accuracy positioning for submersible (resolution of plus or minus 1 cm).

Sediment instability appears to be important as a part of global sedimentary budget. Among the various types of sedimentary instabilities, submarine slides are probably the most spectacular and the hardest to study and predict, although their consequences on human and industrial marine activities can be dramatic. IFREMER is conducting a research project on this topic. An area off Nice (France) has been particularly studied because of its recent activity. Mapping and instability area detection have been carried out. With the possibility of direct interactive observation and highly accurate submarine in -situ operation, the submersible is an extremely efficient tool for sediment studies, but diving purposes have to be precisely defined to provide useful information. In the future, the submersible will still be a major key-tool to study marine sediments, although new systems such as video-ROV will be used complementarily. The present evolution of scientific purposes aiming at a better quantitative comprehension of geological processes might broaden the range of submersible applications in the near future.

Nowadays, side-looking sonar is the only equipment able to carry out long-range underwater imaging. The use of optics is limited to short-range identification by means of conventional video-cameras. However, active optical systems (lidars) manufacturing, using a blue-green laser, will enable optics to hold its place in the field of long-range underwater imaging. After a short comparison between acoustics and optics in underwater detection and a description of the proper features of underwater optical propagation, we present the different conceivable imaging principles and propose a method to determine their performances. The experimentations described concern a lidar imager mock-up using one of the imaging principles proposed. The pictures obtained deal with specular and lambertian targets., Le sonar latéral est actuellement le seul instrument capable de réaliser des images sous-marines à grande distance. L'utilisation de i;optique est restreinte à l'identification courte distance par caméra vidéo classique. Cependant, la réalisation de systèmes optiques actifs (Lidar) utilisant un laser bleu-vert permettra à l'optique de tenir sa place dans le domaine de l'image sous-marine grande distance. Après une brève comparaison entre acoustique et optique sous-marine et une description des caractéristiques propre à la propagation optique sous-marine, on présente les divers principes d'imageur concevables et on propose une méthode d'évaluation de leurs performances. Les expérimentations décrites mettent en oeuvre une maquette d'imageur lidar utilisant un des principes d'imagerie proposés. Les images obtenues concernent des cibles spéculaires et lambertiennes. Sur écho lambertien la portée est de 150 m pour le type d'eau utilisé serait de quelques centimètres. De telles performances permettent d'envisager une utilisation couplée avec un sonar d'imagerie.

Underwater vehicles are used to discover the wrecks, and the author deals with the using of the new marine technology in the archaeology.

This system is composed of a high accuracy hydraulic manipulator arm with 6 degrees of freedom, for high loads (2000 daN), using ultrasound proximetry and contact force measurement data to carry out the subsea connection of bottom oil wells. An expert system controls the connection phases and generates the sequences of commands to be executed by the robot. The safety systems and failure modes are also taken into account. A graphic operator station provides easy control. Each connection phase generates a graphic representation of the robot status and all the proprioceptive and exteroceptive sensors. The control/command system, although it is designed to carry out a subsea connection by means of a manipulator arm, can be adapted to any type of process. For example, it will soon be used to control the decoking process in an oil refinery.

Autonomous Underwater Vehicles, also called "free-swimming vehicles" are self propelled bodies, equipped with their own energy package and with no solid communication link with the surface. At the beginning of the 90s, a renewed interest from the Underwater Intervention Community for autonomous vehicles and quite a number of new projects were announced or started. The present paper aims at presenting an updated State of the Art on the development of autonomous vehicles. It addresses the following points: A brief historical review presents some existing systems and uses. The French experience, in particular, allows to position the potential, and complementary contribution of autonomous vehicles, in a range of various operational systems. A short review of the main developments in the world demonstrates the particular interest for underwater robotics. An analysis of the operational aspects of these various projects leads to a distribution of the different concepts into main classes of mission profiles.