A system of dead weight and equipment on a trolling line with launch and retrieval from a receiving structure of a machine navigating on or in water, the trolling line being continuous and integral with the equipment, the dead weight and the receiving structure and including a first end on the equipment side and a second end on the receiving structure side, the equipment being fixed in a fixed point of the line, preferably at the first end of the line, the line on the second end side being fixed to the receiving structure in a point that is mobile over its length so as to allow the launch or the retrieval of said line, of the equipment and of the dead weight, wherein, at the operational state, said equipment and said dead weight having been launched by unreeling of the trolling line, we find in water, successively: the equipment, a first portion of line of a first determined length, the dead weight, a second portion of line of a second determined length and the receiving structure, and wherein, at the rest state, said equipment, said dead weight and said line are on or in the receiving structure after a retrieval of the line on or in the receiving structure, the system including: - a controllable means for locking and unlocking the dead weight on the line, making it possible, in a locking configuration, to immobilize the line with respect to the dead weight and, in an unlocking configuration, to permit the line to slide with respect to the dead weight, - a first detection means making it possible to detect whether or not the equipment has moved away to a determined distance from the dead weight and corresponding to the first determined length of the first portion of line, - a control means configured so as, in case of an order to launch from the rest state, to successively: - at a step of equipment launch, launch the equipment out of the receiving structure by unwinding of the line, - at a step of dead weight launch, when the first detection means detects that the equipment has moved away to the first determined distance from the dead weight, launch said dead weight and control the locking and unlocking means to the locking configuration while continuing to unreel the line, the line being then immobilized with respect to the dead weight, - at a step of unwinding stop, stop the unreeling of the line when the unwinding of the line has allowed obtaining the second determined length of the second line portion, in the unlocking configuration of the controllable dead weight locking and unlocking means, the line remains linked to the dead weight but is slidingly mobile with respect to said dead weight, the system further including a second detection means making it possible to detect whether or not the dead weight is on or in the receiving structure and in that, at the step of dead weight launch, the control of the locking and unlocking means to the locking configuration results from the detection by the second detection means that the dead weight is not on or in the receiving structure after the launch of said dead weight. - a controllable means for locking and unlocking the dead weight on the line, making it possible, in a locking configuration, to immobilize the line with respect to the dead weight and, in an unlocking configuration, to permit the line to slide with respect to the dead weight, - a first detection means making it possible to detect whether or not the equipment has moved away to a determined distance from the dead weight and corresponding to the first determined length of the first portion of line, - a control means configured so as, in case of an order to launch from the rest state, to successively: - at a step of equipment launch, launch the equipment out of the receiving structure by unwinding of the line, - at a step of dead weight launch, when the first detection means detects that the equipment has moved away to the first determined distance from the dead weight, launch said dead weight and control the locking and unlocking means to the locking configuration while continuing to unreel the line, the line being then immobilized with respect to the dead weight, - at a step of unwinding stop, stop the unreeling of the line when the unwinding of the line has allowed obtaining the second determined length of the second line portion, - at a step of equipment launch, launch the equipment out of the receiving structure by unwinding of the line, - at a step of dead weight launch, when the first detection means detects that the equipment has moved away to the first determined distance from the dead weight, launch said dead weight and control the locking and unlocking means to the locking configuration while continuing to unreel the line, the line being then immobilized with respect to the dead weight, - at a step of unwinding stop, stop the unreeling of the line when the unwinding of the line has allowed obtaining the second determined length of the second line portion,