Platforms resting on an underwater structure

摘要

A platform comprises a base structure designed to rest on the bottom of the sea for supporting an industrial or scientific installation above the surface of the water. The base structure comprises a floatable device capable of keeping afloat and means for ballasting the base structure to install the structure on the bottom of the sea. The base structure also includes a shaft in which a hollow element with a water-tight peripheral wall and a water-tight lower end wall, can slide vertically. The element can be temporarily fixed to the shaft. The element forms a float capable of supporting a deck which carries the installations, but is capable of being immersed over at least the greater part of its height. The deck is capable of floating until it is over the top of the element when the element is immersed and has means for fixing it to the top of the element.