Establishing a shipbuilding production cost structure is a fundamental management activity, concerning materials and fabrication. Shipyards compete in world market niches regarding vessel type and dimensions. Therefore, the vessel's market price has a tremendous influence on the shipyard's determination of the price of the vessel offered to buyers. For this reason, shipyard management is forced to concentrate its efforts on production cost structure optimisation in order to achieve the goal of a profitable shipyard. In this paper, a computer-integrated cost structure optimisation model for defining an optimal and profitable vessel production cost structure is presented. Statistical analysis of the data was performed for a sample of tankers, built in selected shipyards. Probabilistic theory was applied and several results, such as expectation for aggregate figures, are presented. Such a tool for obtaining an optimal production cost structure enables shipyard management to carry out more effective decision-making, and also better cost control within model parameters. Furthermore, dynamical control of costing figures for the whole shipbuilding process is possible and has a significant influence on the final results. The mathematical model for achieving an optimal structure of the production costs was verified and tested against a real example of the construction of tankers.

Sandwich structures are well-known and frequently used solutions in marine applications, especially when structural stiffness is required. An important part of the sandwich structure is the core, which usually carries shear loads. Therefore, choosing a reliable test method and knowing the exact shear properties of the particular core used in the structural design is beneficial for every engineer. Shear properties of the FlexyFoam M-55, a closed-cell, lightweight PVC foam with an apparent density of 60 kg/m³, have been investigated according to the ASTM C273 standard, using the tensile and compressive loading of metal supporting plates glued to the PVC foam sample. A digital image correlation (DIC) technique was used to monitor the crack propagation, and the appearance of secondary stresses at the foam-adhesive interface and strain field for the representative sample was presented. Displacement was measured using the testing machine sensors and compared to the measurements from the DIC technique. Specimen manufacturing details, surface preparation, and the gluing sequence were described, and measuring equipment and experiment settings were presented. Stress-strain curves have been presented and shear modulus and ultimate shear strength of the foam were compared for each test approach. The results were discussed and compared with the manufacturer’s data, as well as with foams of similar densities. The well-established approach in testing the core material was discussed, and recommendations were given to improve the testing procedure.

A larger cruise ship with more capacity enables the ship-owner to gain more profits while at the same time lowering the cost to the client. Cruise ships today have a capacity of about 5,000 passengers, and there are projects in development of cruise ships that will accommodate up to 10,000 passengers. Since such ships have to function as an independent and ecologically sustainable unit during navigation, there is a problem of waste management. This paper presents the methods and procedures for the disposal of liquid and solid waste on cruise ships in accordance with the applicable regulations. Furthermore, proposals for improving and adapting the MARPOL convention to the above trends are presented