The invention concerns a method for mounting a heavy equipment on a floating ship's hull comprising the following steps: (A) securing the equipment to lifting units adapted to be supported on the sea floor, said lifting units being arranged on either side of the equipment; (B) pressing the lifting units on the sea floor; (C) lifting the equipment to shift the ship's hull beneath the equipment; (D) cause the ship's hull to be engaged beneath the equipment in the space defined between the lifting units; (E) lowering the equipment to set it in supported position on the ship's hull; (F) dismantling the units for lifting the equipment; and (G) connecting the equipment to the ship's hull.