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A long-held belief in classical Mediterranean seafaring is that merchant ships were outfitted with heavy weights called dolphins mounted at the ends of yardarms and were defensive weapons dropped on opposing ships to sink them. A review of the iconographic and textual evidence, however, reveals no evidence to support such a weapon was ever used on merchant ships sailing in the open seas, and instead, the textual evidence allows for the possibility that cranes or even catapults were outfitted on ships as offensive weapons as early as 424 BC and on merchant ships, but only under special conditions, in 413 BC. [ABSTRACT FROM AUTHOR]

In commercial ships, wave making resistance is a part of total resistance which to reduce it, a bulbous bow is added to the ship bow. To investigate the effect of bulbous bow on total resistance, a container ship model is simulated with and without the bulbous bow at three Froude Numbers: 0.22, 0.26 and 0.30. Initially, numerical simulation validation has been done, which shows that the results are valid. According to the results, the bulbous bow increases frictional resistance by a maximum of 2%. In these three Froude Numbers, the pressure resistance decreases by 17.1, 31.6 and 25.9%, respectively. At three mentioned Froude Numbers, bulbous bow decreases total resistance by 1.8, 8.9 and 13.3% respectively. In addition, the bulbous bow reduced the height of the wave made on the hull and the free surface. Bulbous bow causes positive effects on the hydrodynamic behavior of the vessel, which increase with increasing Froude Number.

CO2 emissions during ship building, maintenance, and scrapping are not be involved when defining Energy Efficiency Operational Indicator (EEOI). However, these CO2 emissions can only show its value during operation phase of ship life. In order to evaluate the effect of CO2 emissions during ship building, maintenance, and scrapping on energy efficiency, a real time EEOI definition was put forward, a life cycle assessment (LCA) calculation framework was established, and a ship propulsion model with main diesel engine was built. A bulker carrier YUMING was taken as the case ship. CO2 emissions during ship building, maintenance, and scrapping were calculated. Main engine revolution and real time EEOI value with other parameters were obtained by simulating in different ship draft. The results show that life cycle assessment result will explicitly increase the real time EEOI value especially in lower engine speed and lower ship draft. The engine revolution at the lowest EEOI value will increase explicitly by life cycle assessment result. It means that the lower limit of ship speed should increase during slow steaming. Therefore, slow steaming may bring less environmental benefit if the life cycle assessment result is involved. [ABSTRACT FROM AUTHOR]

The impact of the noise radiated from merchant ships on marine life has become an active area of research. In this paper, a methodology integrating observation at a single location and modelling the whole noise field in shallow waters is presented. Specifically, underwater radiated noise data of opportunistic merchant ships in the waters of Zhoushan Archipelago were collected at least one day in each month from January 2015 to November 2016. The noise data were analyzed and a modified empirical spectral source level (SSL) model of merchant ships was proposed inspired by the RANDI-3 model (Research Ambient Noise Directionality) methodology. Then combining the modified model with the realistic geoacoustic parameters and AIS data of observed merchant ships, the noise mappings in this area were performed with Nx2D of Normal Mode calculations, in which the SSL of each ship was estimated using the modified model. The sound propagation at different receiving positions is different due to the shielding effect of islands and bottom topography. The methodology proposed in this paper may provide a reference for modelling shipping noise in shallow waters with islands and reefs. [ABSTRACT FROM AUTHOR]

Two cases of Legionnaires’ disease and 1 of Pontiac fever occurred among the crew of a merchant ship operating off the shores of Australia. PCR assays identified potential sources in the ship’s cabins. Modification of maritime regulations for Legionnaires’ disease prevention in commercial vessels is needed for nonpassenger merchant ships.

To learn the optimal collision avoidance policy of merchant ships controlled by human experts, a finite-state Markov decision process model for ship collision avoidance is proposed based on the analysis of collision avoidance mechanism, and an inverse reinforcement learning (IRL) method based on cross entropy and projection is proposed to obtain the optimal policy from expert's demonstrations. Collision avoidance simulations in different ship encounters are conducted and the results show that the policy obtained by the proposed IRL has a good inversion effect on two kinds of human experts, which indicate that the proposed method can effectively learn the policy of human experts for ship collision avoidance. [ABSTRACT FROM AUTHOR]