No abstract

One of the main problems to be taken into account is the availability of a reliable amount of information during the preliminary design stages. The present paper is focused on the analysis of the results obtained for several versions developed based on the initial version of a river chemical tanker, using a so-called jumboisation which is a technique in shipbuilding, consisting of enlarging a ship by adding an entire section to it. Moreover, the breadth of the prototype ship was also modified in order to evaluate the effects of all these modifications on the performances of the different variants, i.e., hydrostatics, ship hydrodynamic resistances, motorization solutions (main engine selection), EEDI (Energy Efficiency Design Index), etc. Originally, all the investigations have been carried out having as prototype a river chemical tanker of about 4600 dwt, obtaining 7 additional versions. The previous results allow us to develop a synthetic and coherent procedure which can provide a simplified manner to foresee which are the implications and impact of owner’s new requirements on the proposed performances of the new ship. Starting from the obtained results, the present paper is concentrated on the influences when the original ship is converted to a river-sea one, the main expected results being focused on the variation of the maximum values of the bending moments and shear forces acting on the ship girder. The extended calculations of ship resistance lead to higher values of the hydrodynamic forces and then, new main engines have to be selected having significant higher EEDI values. Consequently, the influences due to the modifications can be quantified and the impact as compared to the river ship case becomes possible. The evaluations have been carried out based on appropriate software, provided by Bureau Veritas.

The fore area of the ships in extreme conditions is commonly subjected to external impact pressures such as bottom slamming and bow impact. The phenomenon combined with a poor design can lead to local structural damage (cracks, dents, buckling of plate panels) and malfunction to the installations on-board of the ship. In the present article, a comparison study between different steel material grades is performed for a VLCC fore peak structure subjected to external and internal dynamic pressures under the Harmonized Common Structural Rules for Bulk Carriers and Oil Tankers (H-CSR). Three steel grades generally used in the shipbuilding industry, one normal strength and two higher strength, are subjected for the assessment. The hull structure is built based on the benchmark crude oil carrier KVLCC2 surface developed by KRISO (Korea Research Institute for Ships and Ocean Engineering, and modelled with plate finite elements in FEMAP software. The study targets an optimization process to minimize the steel weight of the structural members by plate elements thickness reduction.

"Considering last year’s climate changes, we can expect low temperatures during winter, which can lead to the freezing of Danube river and more. This would prevent the freight traffic in Danube’s ports meaning that the riparian economy would suffer. This paper presents a new concept of breaking the ice. Using an existent tug, we propose the attachment of an icebreaking additional structure. The paper further describes the concept and includes the necessary calculation methods used for the technological design of this ensemble. This concept presents numerous advantages, including the financial aspect."

"During the shipbuilding processes carried out in the shipyards, there is a need to transport the sections of ship structure, from the place where they are built to the assembly location. When the shape and structure of the sections allow, they are built in an inverted position, and after finishing all the works that can be performed in this type of placement, the section will have to be turned to continue the section building process and subsequent the assembly. Loads that appear in the structure during these maneuvers are different from those that appear during the operation and from those for which calculations were made at the stage of the initial project. Therefore, it is necessary to calculate them and design a lifting / turning installation, which should also contain stiffening elements where required, in order to prevent both accidents and deformations or detachments that could occur at the section level. From this necessity appears the plan generically called ""lifting plan"" and which contains the installations, the schemes, the necessary instructions to remove the units from the section building hall, turn it to the gantry cranes and brought into the mounting position."