Design study for the transportation of heavy cargo on hatch cover of a MPV

Abstract

With the current scenario and as per the demand of the offshore industry market, especially in the Scandinavian coastal region which exhibits shallow draft, SAL Heavy Lift GmbH aims to strengthen its presence by offering heavy lifting of offshore equipment like reels, carousels etc. with their state of the art vessels like PK 116, SAL 161, SAL 183 etc. that possess high stability in shallow draft with large crane and cargo hold capacity. However, heavy cargo with tiny footprints may cause strength problems in the deck area, especially for the PK 116 vessel due to its limited deck strength capacity. To overcome this hurdle, the company decided to strengthen its weather deck such that it can withstand heavier cargo on top of it without compromising its stability in the shallow draft region. The work scope of the thesis comprises with the vessel PK116 which was minutely interrogated in all aspects to overcome the above obstacles. First of all, the whole vessel with its entire longitudinal and transversal member including Holes and cut-outs was modelled using the Software “POSEIDON”. Next, strengthening of the Weather Deck was done by modelling the stanchion using AUTOCAD and later on in the POSEIDON as well. The main task was to design and estimate the number of stanchion which can transfer the load from main deck to the double bottom in an efficient manner. After completion of the vessel modelling, the FE-model was generated using Poseidon and then imported in to the “Shipload” to model mass distribution for calculating the hydrostatic equilibrium. After hydrostatic, linear hydrodynamics were calculated to generate load cases and then finally these nodal loads were imported back to FE software again to compute the global strength analysis of vessel. After successfully analysing the global strength analysis of vessel, the stanchion design were estimated by calculating the total load on the stanchion members. At last, Deformation, yield stress and buckling check were done to ensure the stanchion design is withholding the designated load on hatch cover / weather deck and successfully transferring in to the bottom structure.