国内渔船与远洋渔船实用稳性衡准的探讨

Discussion on practical stability criteria of domestic fishing boats and ocean going fishing boats

为避免渔业船舶工作者在校核国内渔船与远洋渔船稳性时产生规则上的混淆,降低错用的风险,对国内渔船与远洋渔船在实用稳性衡准方法上进行差异比较、归纳总结,并提出了纵倾状态下初稳性高度的推导意见。通过比较发现:1)两者在校核稳性时所用的数学模型不同,但基本原理一致,都提出了气象衡准数K≥1的要求。2)计算风压倾侧力臂所用的公式相同,但公式中风压P、风力作用力臂Z的取值方法不同。3)计算横摇角φ所用的公式不同,且涉及公式中参数的取值时,初稳性高GM、船长L的含义不同。4)无论何种作业,远洋渔船对复原力臂曲线下的面积都有最低要求,而国内渔船仅在作业方式为桁拖网时,才有此要求。另外,校核稳性时还应注意:对装船使用后不存在位置移动且重量不会减少的物体应计入空船重量中;渔捞网具及索具的重量应是湿重状态下的重量;计入稳性计算的上层建筑或甲板室等围蔽结构应符合规则中对干舷的相应要求;应根据实际情况对自由液面、悬挂载荷、渔具操作横倾力矩、纵倾状态下的进水角进行修正。本文还对如何计算纵倾状态下的初稳性高度提出了推导意见。

In order to prevent the fishery boat workers from confusing the rules in the work of checking stabilities of domestic fishing boats and ocean going fishing boats,and reduce the risk of misuse,the paper compared and summarized the differences of practical stability criterion methods between domestic fishing boats and ocean going fishing boats,and put forward the deduction of initial stability height under longitudinal inclination. Through comparison,we found that： 1） Although the mathematical models of the two stability criteria were different,the basic principles were consistent,they both put forward the requirement of weather criterion number K≥1. 2） The formulas to calculate the wind heeling arm were the same,but the methods of taking values of the wind pressure P and wind acting lever Z were different. 3） The formulas to calculate the roll angle were different,and the meanings of initial stability height GM and ship length L were different in formula. 4） No matter what kind of operation,the ocean going fishing boats had the minimum requirement for the area under the righting arm curve,while the domestic fishing boats had the minimum requirement for the area under the righting arm curve only when the operation mode was a beam trawl. In addition,in the work of checking stability,we should also pay attention to that： the weight of the objects which won＇t move and won＇t reduce weight after shipment should be included in the weight of the empty ship; the weight of the fishing nets and rigging should be calculated in the wet weight state; the enclosed structure such as the superstructure or deck room which was included in the calculation of stability should comply with the relevant requirements of the rules in the freeboard; the inlet angle of the free surface,the suspension load,the fishing gear operation,the heeling moment and the longitudinal direction should be corrected according to the actual situation. This paper also proposed some opinions on how to calculate the initial stability height under the state of longitudinal inclination.