Abstract: The equipped deck (1) is charged onto a self-elevating platform (2). The platform is positioned close to the fixed platform (11) and the deck is lifted from the self-elevating platform (2) to the level of the fixed platform (11). The deck is slid on the fixed platform (11) by means of a cradle (6) mounted on blocks provided with regulating jacks. The blocks co-operate with sliding ways provided on each of the platforms. The two platforms are coupled by means of a guiding frome (12).