One of the most issues on a boat for using energy is resistance. Therefore some energy is needed to be able to overcome the boat resistance. The total resistance depends on the speed of the boat. By reducing the resistance, it will affect the energy usage on the boat. One way to reduce the boat resistance is by installing a stern flap to the stern. Stern flap is a new addition on the stern appendage. Previous studies, the stern flap was able to reduce the resistance. The reduction of resistance occurred on boats can reduce fuel consumption, so it can be one of the innovations in combating the energy crisis. This study used an experimental method that analyzes the position and size of the stern flap, where each position and size of the flap were tested at the same load. From the results and analysis, it shows that the changing position of the stern flap on the surface of the water will increase the boat speed by 4.62% and the changing size of the stern flap size to 85 × 80 cm will increase the speed of the boat by 3.82%.
In order to save spaces inside a small-sized fishing boat, the high-pressure flow behind propeller is utilized instead of a special cooling pump to cool the main engine. From the previous study, the system is referred to as the Propeller Flow Cooling System (PFCS). As a continuation of the previous study, the present study conducted more experiments in order to compare the performance of a single and a double intake designs of the PVCS with the same cross-sectional area. The designs with circular and elliptical intakes shapes were measured. The experiments were also conducted at the Circulating Water Channel (CWC) facility. The main parameter which was compared in the experiment and analysis was the flow capacity produced by both designs for various propeller revolution (RPM). The experimental results showed that single intake design has a higher flow capacity than the double intake one which was caused by higher flow losses inside the pipe of single intake design mainly due to higher surface friction as well as an additional elbow joint needed in double intake design. This tendency occurred for both circular and elliptical shapes cases.
The condition of the Indonesian fleet, which is in its old age, allows ships to be recycled as the best solution. However, conditions in the field, there are still many ship recycling processes that do not obey the rules, especially on the effect of workers and also the effect on the environment. In Indonesia, there are still many ship recycling yards that do not pay attention to the effects on workers and the effects on the environment and most of them are still traditional shipyards. Therefore, one of the best solutions is to renew existing regulations, namely the Hong Kong International Convention for The Safe and Environmentally Sound Recycling of Ships. When the implementation of this convention, the ship recycling shipyard must adjust to the convention. This study focused on the analysis of the assessment of the condition of Occupational Health and Safety (OHS). To evaluate the condition of the shipyard, the Gap Analysis method is by comparing the ideal conditions with the existing conditions at that time. The analysis is carried out using the Hazard Identification Risk Assessment Risk Control (HIRARC) method. This method is carried out by identifying hazards, which then provides a risk assessment and recommends how to control it. Based on result, risk matrix were obtained, which contained the assessment categories of Low, Moderate, High and Extreme. The results of this study through the gap analysis method, the average value is 2.1, which means that this value is still very low because the value of 0 - 2 is categorized as still many sub-clause indicators that do not exist or are not handled. Furthermore, in research using the HIRARC method, 60 risk matrices were obtained, which contained the assessment categories of Low, Moderate, High and Extreme.
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