Abstract: The invention relates to towed acoustic transmitters forming an underwater vehicle which is itself intended for towing a linear acoustic receiving array (105). It consists in placing the vertical faired acoustic array (303) of such a transmitter at the very rear of the underwater vehicle, and in balancing the weight of this array by a faired ballast (313) situated at the very front thereof. These two parts are joined by a girder (310) of small cross-section, and the center of gravity of the whole is situated at the front of this girder and beneath it. The vehicle is towed by a cable (101) fastened to the vehicle by a hook (314) fixed to a swivel joint (315) above the center of gravity. It makes it possible to facilitate the operations of submersion and fishing-out of the whole while also achieving a greater depth of submersion.

Abstract: A winch makes it possible for a fish fitted with sonar to be towed behind a boat. The winch includes a sensor for measuring the attitude of the fish and a device for controlling, using this measurement, a servo cylinder actuator which alters the inclination of the jib to keep this attitude constant. The winch makes it possible to reduce jerks in the tensile stress applied to the cable which tows the fish.

Abstract: In a device for the suspension of a sonar acoustic base within its protection dome, two connection rods are used. These two connection rods are hinged, by one side, on the hull of the ship and, on the other side, on the acoustic base. These connection rods form a triangular system which, during the motions of the base, dictates a rotation of this base about an instantaneous center of rotation R located above the center of gravity G of the base. In this way, when the base touches the internal surface of the dome, the impact occurs as a surface-to-surface impact and not as a corner-to-surface impact. This limits the damage caused by the impacts, thus making it possible to obtain, simultaneously, a very free suspension of the acoustic base and efficient protection of the sonar dome.

Abstract: The disclosed mechanism is designed so as to be impervious and give a motion of translation enabling, for example the driving of a hinged arm. The mechanism has a hydraulic circuit with fluid, a jack associated with a pull-back spring and a pump to bring the jack to the working position. The pump is actuated by a motor. The pump and the motor are entirely placed inside a common enclosure so that the motor, with its shaft, bathes in the fluid of the hydraulic circuit. The mechanism is designed for sonars, to unfold and fold their antennas mounted on hinged arms.

Abstract: Disclosed is a mechanism comprising an arm hinged on a connecting rod to make a choice, on the basis of a translational motion along two opposite directions, between "lowered arm" and "outstretched arm" positions that are substantially orthogonal to each other. In this mechanism, the rod and the arm, when the latter is lowered, form an obtuse angle, and the rotation pins other than the pin common to the rod and to the arm are fixed as regards the pin of the connecting rod, and undergo translational motion as regards that of the arm. The free end of the arm coming to the lowered arm position thus follows a trajectory with downward sliding and passage through a "hard point" which ensures that the arm is efficiently kept in the lowered position.

Abstract: A depresser designed to keep a fish, towed by a ship, submerged comprises a flat swept wing joined to the towing cable by means of three suspenders making it possible to set it at an optimal angle of incidence. This enables a fish to be towed at a high speed which may go up to 30 knots while, at the same time, keeping it at a substantially constant depth of submersion.

Abstract: In a sonar buoy suspended from a helicopter, the lower stabilizing ring of a buoy of this type is replaced by a set of fins which get folded against the body of the buoy during its descent into the water and get unfolded when they are raised again to form a stabilizing crown around the bottom of this body, thus enabling a buoy of this type to be stabilized both during descent and when being raised again.

Abstract: A buoy released from an aircraft for carrying out under water listening includes a balloon fixed to a body by way of a set of halyards extending from the top to the base of the balloon and fixed inside the neck of the body of the buoy. The inflation air penetrates into this neck then into the balloon through triangular openings formed in the neck. A textile sleeve fixed to the internal wall of the neck above the inflation openings turns inside out after impact on the water so as to close these openings, which avoids deflation of the balloon and loss of the buoy.