This paper presents dimensioning and operational benefits of the CRP Azipod®propulsion system. The system dimensioning is based on the data received from model tests conducted at the Samsung Ship Model Basin in South Korea. The CRP Azipod® propulsion system demonstrated the best hydrodynamic efficiency as well as the best total propulsion efficiency, when the CRP Azipod® was compared with a twin-screw twin-skeg system and a singlescrew system in model tests. As an example, dimensioning of the CRP Azipod® system for the ULCS, Ultra Large Container Ship, is presented in detail and differences among these propulsion systems are considered. Finally, an operating cost comparison between the CRP Azipod® and the twin-screw twin-skeg system for the 12000 TEU ULCSs is presented. It clearly reveals the CRP Azipod® system is the most efficient propulsion system when operating costs are considered.
Generally today, there are three types of sterntube seals and those are water lubricating type, oil lubricating type and air type which air chamber is provided. And for all of types it is common sense that exchange of sealing ring, Viton or NBR, is necessary regularly. But the material of sealing ring for this“SIMPLAN Shaft Seal”is Silicon Carbide and it realizes the condition that it is no necessary to exchange sealing ring semipermanently and help to reduce maintenance cost of the ship. Furthermore seal body can keep constant pressure against sealing ring and it also helps to improve the performance of the sealing system. It was developed and it is sold by B+V Industrietechnik GmbH in Hamburg, Germany.
Future preventive maintenance system (PMS) wear tests for diesel engines may include analysis of lubricating oil to detect a foreign metal that has been purposely embedded at a specified depth below a sliding surface. Our experiment used cobalt (Co) embedded in a piston ring and barium (Ba) embedded in white bearing metal. A pin-on-disk wear test of each material showed that cobalt may be applicable to oil analysis for preventive mainte-nance. More consideration is needed, however, for such use of barium.
Probabilistic safety assessment (PSA) has come to occupy an important position in quantitative reliability evaluation for large-scale systems. Fault tree analysis and event tree analysis are already popular and very effective methods of quantitative evaluation. These methods, however, are not easy for many common users. GO-FLOW methodology is not only effective but also convenient for practical use in large-scale system reliability evaluation. It can be considered that a ship is a huge plant or a large-scale system. Because a ship cruising at sea can never simply obtain help from others, it is important that high reliability and self-contained repairability be provided for safe operation of the ship. GO-FLOW methodology is an effective means of conducting probabilistic safety assessment on a ship as a system. The purpose of this study was creation of a reliability model (Ver. 2) and a probabilistic safety assessment for the propulsive plant on the ship. Actual safety of the propulsive plant on the ship was made clear by quantitative analysis using GO-FLOW methodology.
In the first paper, the results of wear tests on anticorrosive platings in seawater were reported at a fixed very low sliding speed under different potentials. The primary result showed that Ni-base plating generally had better corrosive wear resistance than Cr-base plating. In the present study, a wear test was carried out to clarify the effects of sliding speed and facing materials (Al2O3, SUJ2, and identical plating) on corrosive wear characteristics of Ni, Ni-P, and Cr platings. The results indicated that each type of plating is differently affected by each sliding speed and facing material. Cr plating shows a lower wear rate than the other platings over a wide sliding speed range and for all facing materials, and therefore is proposed as a repair material for worn surfaces of machine parts. Ni plating suffers severe surface damage from adhesive wear when sliding against the identical plating. The wear rate of Ni-P plating increases rapidly with an increase of sliding speed. Mechanical wear through adhesion seems to be a more dominant damage mechanism than chemical corrosion by seawater under this test condition.
Propulsion by oscillating a wing in a fish-like tail fin stroke has been proposed as a novel system with higher propulsive efficiency and greater safety than a conventional screw propeller. This paper describes the development of an outboard propulsor using an oscillating wing that is movable and is easy to attach to and detach from a small boat. The behavior of the oscillating wing coupled with the heaving and the pitching motions was realized by use of a new designed crank mechanism with L-shaped links. The propulsive performance of the outboard propulsor using an oscillating wing was investigated. As a result, it was found that the speed of the boat equipped with the outboard propulsor was proportional to the frequency of the oscillating wing. It demonstrated that the outboard propulsor is good for such small boats as fishing boats and pleasure boats as an environmental friendly propulsor.
The rate of heat release in the experiment was simulated using a numerical computation code (KIVA-3V), and the combustion process was inferred from the spatial distribution of the temperature and of the fuel and oxygen concentrations in the combustion chamber. Results confirmed that covering the nozzle positioned downstream in the noz-zle-array with the burned gas causes the first peak in the rate of heat release in a multi-nozzle, side injection diesel engine. The second peak in the rate of heat release is related to the ratio between the injection period and the period from the injection start timing to first peak time. Swirl flow is a dominant factor in the profile of heat release rate, because swirl momentum, rather than injection momentum, strongly affects the tip penetration of flame jet.