Device acting on a structure designed to tilt from a first edge to a second opposite edge, with the device comprising: - at least one intermediate chamber (17,170a,170b) which is elongated between the first and second edges, - a first side tank and a second side tank (15a, 15b) both communicating with the intermediate chamber(s) to manage liquid inputs and outputs, the side tanks each including a wall which delimits said side tanks externally and being located towards two extremities of the intermediate chamber, - with each side tank comprising: -- an upper section (150a, 150b) positioned so that it receives the liquid in line with the elongation direction (17a, 17a1, 17b1) of the intermediate chamber which supplies it, -- and a lower section (152a, 152b) which communicates (in 21a, 21b) with the upper section, with each of the upper and lower sections being in communication with the intermediate chamber(s) for the liquid inlets and outlets, characterised in that each communication between the upper section of the corresponding side tank (15a, 15b) and the intermediate chamber is positioned so that the liquid channelled by the intermediate chamber (17, 170a, 170b): -- enters said side tank tangentially to a part of the wall which delimits the corresponding side tank externally, at the entry of said tank, and -- so swirls around a vertical axis (110a, 110b), when said liquid is evacuated towards the lower section of said tank. - at least one intermediate chamber (17,170a,170b) which is elongated between the first and second edges, - a first side tank and a second side tank (15a, 15b) both communicating with the intermediate chamber(s) to manage liquid inputs and outputs, the side tanks each including a wall which delimits said side tanks externally and being located towards two extremities of the intermediate chamber, - with each side tank comprising: -- an upper section (150a, 150b) positioned so that it receives the liquid in line with the elongation direction (17a, 17a1, 17b1) of the intermediate chamber which supplies it, -- and a lower section (152a, 152b) which communicates (in 21a, 21b) with the upper section, with each of the upper and lower sections being in communication with the intermediate chamber(s) for the liquid inlets and outlets, characterised in that each communication between the upper section of the corresponding side tank (15a, 15b) and the intermediate chamber is positioned so that the liquid channelled by the intermediate chamber (17, 170a, 170b): -- enters said side tank tangentially to a part of the wall which delimits the corresponding side tank externally, at the entry of said tank, and -- so swirls around a vertical axis (110a, 110b), when said liquid is evacuated towards the lower section of said tank. -- an upper section (150a, 150b) positioned so that it receives the liquid in line with the elongation direction (17a, 17a1, 17b1) of the intermediate chamber which supplies it, -- and a lower section (152a, 152b) which communicates (in 21a, 21b) with the upper section, with each of the upper and lower sections being in communication with the intermediate chamber(s) for the liquid inlets and outlets, -- enters said side tank tangentially to a part of the wall which delimits the corresponding side tank externally, at the entry of said tank, and -- so swirls around a vertical axis (110a, 110b), when said liquid is evacuated towards the lower section of said tank.