مهندسی دریا
Ataollah Gharechahi; Esmaeil Shafizadeh
Abstract
In this research, the effect of weights that lose their lashing systems and can move freely in line with vessel breadths is investigated on ship roll motions. Therefore, the effect of friction and possible barriers that impeded on free movement of weights are neglected.To study the effects; weights with ...
Read More
In this research, the effect of weights that lose their lashing systems and can move freely in line with vessel breadths is investigated on ship roll motions. Therefore, the effect of friction and possible barriers that impeded on free movement of weights are neglected.To study the effects; weights with different masses are hung on pendulum which is installed on an ocean going trawler model and vessel roll motions is being experimentally tested.The results show that whoever hanging weights can increase the center of gravity of vessel and decrease the vessel stability; but caused increase the period of roll motions. The findings of research also can be used in design of damping systems of roll motions.In addition, the experimental results are compared with numerical results based on the Strip Theory. The results show that the damping coefficient has important role in the accuracy of numerical results.
مهندسی دریا
Ataollah Gharechahi; Mohammad , Rahimi
Abstract
In this paper the amount of pollution produced by boats with 2-stroke engines have been calculated, in different seasons in southern coast of Iran. The seasonal activity of boats is estimated based on the average of wide range of expert opinion whom familiar with these type of vessel according to crowd ...
Read More
In this paper the amount of pollution produced by boats with 2-stroke engines have been calculated, in different seasons in southern coast of Iran. The seasonal activity of boats is estimated based on the average of wide range of expert opinion whom familiar with these type of vessel according to crowd wisdom theorem. Also the amount pollution per hours power of engine is derivates from similar international researches.The results show that the proportion of pollution from these boats is about 290 times greater than pollution from stern tube and deck machinery leakage from vessels in southern Iran. In particular, they are contains toxic compounds of BTEX which is generated in way of marine life near coastal waters. In spring and winter the pollution is greater than other seasons. with emphasis on the Persian Gulf and Oman Sea are the “Especial Area” and the threat of activity of boats on marine life; Suitable solution to reduce the pollution from these vessels, Should be in priority program of coastal countries especially the Islamic Republic of Iran .