Structural Design and Stability of a 6,000 ton capacity Floating Dry-dock

Abstract

This thesis work is focusing on the design and analysis of a Floating Dry Dock complying with DNV-GL Rules with emphasis on the structural design and stability. The mentioned work was carried out during the internship in Nelton Sp. z o.o. located in Szczecin from July 3 till November 8 in the year 2017. Floating Dry Docks are being widely used for the construction of ships, docking of ships for inspection and repairs and also for ship launching. One of the major advantage of floating dry docks from the graving docks is mobility. And a floating dry dock doesn’t require any yard space. Floating dry docks are built to different lifting capacities, and there are different types of designs available as well based on the requirements. With the requirement for a pontoon type floating dry dock with 5 modules of pontoons and 2 dock wings which can be dismantled, the design is carried out for the same with an appropriate connection between the pontoons and the wing tanks. Just like any other structure, the safety is of prime concern and hence various classification societies developed rules for the design of floating dry docks with regard to the structural design, stability, machinery, other safety and protection systems and survey requirements. Current work is based on the rules developed by DNV-GL. With a stability check based on approximated weights available, the work carried out involves the global structural design, with adequate connections between different modules. With structural design in place, more or less actual weights of the structure is calculated and then the stability check is done based on that. Based on a feasibility check, the capacity and dimensions of this floating dry dock is found suitable for the construction of all the types of submarines which are currently under consideration by the Polish Navy.