Dry dock at Genoa

Abstract

After elaborate planning, the building, towing and sinking of the ship repairing dry dock at Genoa has now been completed. The dock is 260x52x21.5 m in size. Its structure is cellular and it is made of reinforced and prestressed concrete. A special feature of this dock is that it rests on a flexible bed of sand, dredged from the sea bed. To prepare this, the following operations were carried out: mud was first dredged away, the stony outcrops were levelled off, the spaces in between the rocks were filled with concrete, then the layer of sand was placed, and finally a surface of larger aggregate was prepared on top. The method of attaching the dock to the sea bed to ensure its stability is also noteworthy. After much thought, it was decided that once the dock was sunk at its final emplacement, if its cellular compartments were filled with sand ballast, its own weight would ensure its permanent stability in the face of rough seas. The maneuvers for floating the dock, and sinking it, were also complex, since it was essential to take carefully into account the state of the weather. Any storm might have severely damaged the dock's cellular structure. The prefabrication of the caissons, the jointing of them into a large structure, the construction of enclosing walls, the provision of galleries, companionways, and housing facilities inside the dock, and the towing, sinking and ballasting of this large and heavy structure, constitute a series of building and navigational operations of great complexity, which have tested the ability of the firm Fincosit, who specialise in hydraulic projects.