Abstract: The present invention concerns marine platforms designed for carrying out drilling operations at sea. More precisely, it concerns platforms equipped with a number of retractable pads, which, in the retracted position, allow the platform to be moved by flotation, and, in the support position on the sea bottom, allow the platform to be raised above the surface of the sea by means of elevator devices, consisting of at least a pair of pinions for each pad, these pinions engaging with racks provided for the purpose. According to the invention, the safety device includes, for each pinion-equipped pad (1), at least one pair of pinions (8-9) mounted on a support chassis (12) attached to the platform, together with a brake on each pinion axle (10-11) engaging the same side of the rack. The preferred manner of attaching the support chassis to the platform is by means of a joint mounted on an eccentric (14) which allows for horizontal displacement to compensate for lateral play using a cam, for example.