Propulsion system is one of ship systems which require more attention, especially on propeller design. The propeller design greatly affects the ship speed. It is expected to be able to have maximum value of thrust coefficient and efficiency. Hence, the optimum design of propeller can be obtained by multi objective optimization process. In this study, a preliminary optimization is applied to B-series propeller with the Non-dominated Sort Genetic Algorithm-II (NSGA-II). The purpose of this study is to find out the optimum performance of B-series propeller. The thrust coefficient and open water efficiency are maximized in the optimization process which are then subjected to constraint function imposed by required thrust. The optimization is carried out to blade number Z=3 and Z=5. The population of design space is obtained after running the optimization program. The final optimum design parameter is considered using crowding distance value in the population. The result obtained by NSGA-II showed that the optimum design for Z=3 are B3-787, B3-314, B3-560, and Z=5 are B5-416, B5-501, B5-476 respectively. In addition, the Computational Fluid Dynamics analysis (CFD) is employed to investigate the characteristic of each propeller model by using Multi Reference Frame (MRF) approach. The CFD results showed that the highest thrust value of the Z=3 is 172.38 kN generated by the B3-787 whereas the highest thrust value of Z=5 is 168.80 kN generated by the B5-501 model.

Ocean waste that continues moving in the water has been a problem until now. This has stimulated marine debris cleaning technology to emerge. This research sought to evaluate the effectiveness of waste collection using a monohull and catamaran fitted with a forward conveyor. The Reynolds Average Navier Stokes (RANS)-based numerical simulation research is used to predict flow pattern characteristics, velocity contour, wave pattern, pressure distribution, and ship resistance. The current research focuses on the impact of a round-bilge-type monohull and inner flat-type catamaran hull front shape on waste collection behavior by applying numerical methods. The multiphase solver numerical configuration supplied with OpenFOAM v2112 has been verified and validated using the Delft catamaran 372 with Froude numbers 0.3. The effect of free surface on resistance and flow characteristics was evaluated by comparing these two models. The results show the behavior of marine debris collection due to the flow characteristics of both models. The marine debris flows much more conveniently through the conveyor fitted in front of the catamaran model than in the monohull model. In addition, considering the front-side hull flow, the catamaran model is superior since marine debris is able to approach the ship easily. However, the monohull model is faster at bringing marine debris closer to the conveyor, particularly at the location in front of the conveyor.

In this paper, an attempt has been made to assess how effective waste-collecting uses the conveyor wing. This wing-equipped conveyor will later be installed in front of the ship. In this work, a simulation model is a conveyor and wing without the ship. A numerical investigation based on Reynolds Averaged Navier Stokes (RANS) for predicting the flow pattern characteristics, velocity contour, and resistance. The focus of the present study is the impact of wing shape on waste collection in calm water through the application of numerical methods. The three variations of wing shape used are solid wing shape, square hollow wing shape, and circle hollow wing shape. It is done using speed variations of 1 to 12 knots. From the analysis of velocity contour, circle hollow wing is faster in collecting waste, then followed by hollow square wing and solid wing. From the flow pattern analysis, the circle hollow wing model is easier to make ocean waste come closer to the winged conveyor than the square wing and solid wing model. It is known that winged conveyors can only be used to collect ocean waste at low speeds. Then based on resistance comparison, it is also known that the resistance of winged conveyors from the largest to the smallest is the solid wing, hollow circle wing, and hollow square wing, respectively.

The Citarum River flows through different characteristic of terrestrials with 297 km length and become one of the largest rivers in West Java. It potentially transfers debris from land into the sea. This research aimed to define the Marine Debris (MD) trajectories based on seasonal monsoon. The...

The increase in ocean waste continues to grow from year to year, especially plastic and solid waste. Various ocean waste collection ships using conveyors exist, both in the form of designs and already in operation, but there has been no research on how many hulls are suitable for ocean waste collectors. This study aims to choose between the three-ship models, namely monohull type U, catamaran type inner flat hull, and trimaran type symmetrical. Assessment is based on ship resistance which relates to fuel consumption and flow distribution relates to ocean waste collection. This research uses Computational Fluid Dynamics (CFD) method which produces resistance, fluid flow velocity contours, and fluid flow patterns. Numerical simulation is based on Reynolds Averaged Navier Stokes (RANS). The turbulent model uses the standard k-epsilon equation. Then the volume of fluid sub-models used is open channel flow. The number of eulerian phases is two. Moreover, formulation of the volume fraction parameters used is an implicit body force. The results show that monohull type U is better than others in easiest to bring ocean waste closer to the conveyor and smallest resistance force. Then symmetric trimaran is faster than others in making ocean waste flow to the conveyor.