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液货船检查手册VIQ7和VIQ6比较有哪些改变?

新闻来源:中国船检    浏览量:405 CTASF 2018-08-28
         第089期
        [问题来源]:
        OCIMF在2014年启用的VIQ8.10中要求“船长是否了解稳性手册内的最差破舱稳性状况?”。该要求从一开始实施就引起了业界较大的争议,问题是该条文没有“最差破舱稳性”定义。
        [分析意见]:
        船舶的最差破舱稳性可以是指GZ(复原力臂)不足,也可以是初始稳性高度不足,鉴于该“最差”涉及了二个不同的指标,按照通常的解释是: “两个方程和两个未知数,理论上有唯一解。但是由于浮式海洋结构物浮体几何形状的复杂性,浮力和浮心位置没有解析表达式,因而该方程也无解析解。”因此,即将于2018年9月底启用的VIQ7,把歧义性要求由下列条文正式取代,(仅仅摘录前半部分,另外是和VIQ6中检查要点不同处,用红色文字表达)。
        VIQ7- 8.5 是否准备了货物装载计划,该计划应按货物和压载操作中含有应力、完整稳性和破损稳性的详细规划,是否有任何操作限制?如适用时,是否有货物值班人员理解并清楚的书面文件和记录?
        检查人员应确认船上在货物操作前已有包括初始、中间、结束操作阶段的稳性、应力的计算。
        整个货物操作过程中应实时监控船舶应力和稳性的状态,以确保其状态始终保持在限定范围内。
        所有货物操作应事先做好详细书面计划。详细的计划自始至终经过了船上和码头双方所有操作人员的讨论。计划在咨询码头和随着码头/船上环境的变化后有可能需要修改。任何修改计划应形成正式记录并且要让所有操作人员有所警觉。ISGOTT第22章含有详细的货物计划和它们间的环境。 
        (ISGOTT 11.1.1)
        注:计划应包含操作的所有阶段,至少应包括:
        ● 每一票货物的数量和等级;
        ● 密度、温度和其他有关性能;
        ● 货物积载图,将使用的管路和泵;
        ● 装卸速率和最大许可压力;
        ● 操作的关键阶段;
        ● 速率变化的通知;
        ● 透气要求; 
        ● 稳性和应力资料;
        ● 吃水和吃水差;
        ● 压载水操作;
        ● 应急停止程序;
        ● 溢油应急程序和溢油回收;和 
        ● 该货物的危害特性。
        如要求,还应包括:
        ● 预防静电产生;
        ● 最初开始装卸速率;
        ● 货物加温系统的控制;
        ● 清扫管线;
        ● 原油洗舱程序;
        ● 富余水深的限制;
        ● 加装燃油; 
        ● 针对该货物的特别预防措施。
        ● IGS操作
        货物积载图必须由负责的值班驾驶员在开始卸货前验证并经船长批准,必须用浅显明了的解释,能让操作者理解所有操作细节。
        船舶必须确认在货物操作前,已完成了对货物管线联通时包括通风进行了独立的检查。
        记录应包括所有主要事件的详情,包括主货泵和压载泵启动和停止,正在操作的舱室及偏离原计划的情况。
        船长和大副应知道船上现在装载状态下的最坏破损情况。
        结论和建议:现有结构的常规双壳油轮,基本上不会出现稳性高度不足的现象,建议关注单边破损时出现的复原力臂值不足问题,为便于船员更加准确理解该条文,建议进一步查阅船上的装载手册或者通过计算机离线模拟方法得出结论。
        另外要给出较完整的有关稳性满足业界需求的内容,还需要后续补充说明,限于篇幅将在后期再做介绍。
        (附英文原文)
        8.5 Has a cargo plan been prepared and followed with a detailed sequence of cargo and ballast transfers documented, stress, intact and damage stability and are any limitations, where applicable understood by the cargo watch officers and clearly documented? 
        Inspectors should determine that prior to transfer of cargo, calculations have been made for stress and stability conditions for the start, interim and completion of transfer conditions.  Regular monitoring of stress and stability should be taking place throughout cargo transfer to ensure that the conditions have been maintained within design limits. 
        All cargo operations should be carefully planned and documented well in advance of their execution. 
       The details of the plans should be discussed with all personnel, both on the ship and at the terminal. Plans may need to be modified following consultation with the terminal and following changing circumstances, either onboard or ashore. Any changes should be formally recorded and brought to the attention of all personnel involved with the operation. ISGOTT Chapter 22 contains details of cargo plans and communications regarding them.  (ISGOTT 11.1.1) 
        The plan should cover all stages of the transfer operations and as a minimum, contain: - Quantity and grade of each parcel; 
        - Density, temperature and other relevant properties; 
        - A plan of the distribution, lines and pumps to be used; 
        - Transfer rates and maximum allowable pressures; 
        - Critical stages of the operation; 
        - Notice of rate change; 
        - Venting requirements; 
        - Stability and stress information; 
        - Drafts and trims; 
        - Ballast operations; 
        - Emergency stop procedures; 
        - Emergency spill procedures and spill containment; and - Hazards of the particular cargoes. 
         And also, as required: 
        - Precautions against static generation; 
        - Initial start-up rates; 
        - Control of cargo heating systems; 
        - Line clearing; 
        - Crude oil washing procedures; 
        - Under keel clearance limitations; 
        - Bunkering; and 
        - Special precautions required for the particular operation - Inert gas operations. 
        The cargo plan should be completed by the responsible officer prior to commencement of operations and verified and approved by the Master. It should be comprehensive, contain full details of the operation and be easy to interpret.  Vessel should be able to demonstrate that an independent check of the cargo line up including venting was carried out prior the start of the cargo operation. 
        The cargo log must include details of all major events including starting and stopping of main cargo and ballast pumps, tanks being worked and any deviations from the original plan. 
        The master and chief officer should be aware of the worst case damage condition for the existing cargo onboard. 
        专家审稿:方玉林(CCS)
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