Abstract: The DNV·GL new rules give the clear requirements for the general design of the open-top multi-purpose vessels. It is necessary to study the changes of the new rules and their influences on the general design of the open-top multi-purpose vessels in order to guide the subsequent research and development design. The changes of the new rules include the most unfavorable spectrum peak period, trim, initial metacentric height and intact stability of the cargo hold after being flooded during the open-top seakeeping model test. The influence of the new rules on the longitudinal strength and the bilge draining system has been analyzed for the 13 000 DWT open-top multi-purpose vessel. The seakeeping model test of the type III open-top multi-purpose vessel is also compared to summarize the measures to reduce green water. The overall longitudinal bending moment and the shear stress of the hull decrease significantly due to the reduced requirement of the water intake height of the cargo hold, which can further save the hull structural steel. The new rules also improve the redundancy of the bilge draining system of the cargo hold, where the redundancy is not only demanded for the bilge pump but also for the bilge piping system with the special emphasis as an annular piping system. The most effective way to reduce the green water is to locate the superstructure at the bow of the ship with the width of the superstructure arriving at the ship breadth, or to install the wave shelter or breakwater with the certain width and height on the bow of the ship to effectively block green water.

Key words: open-top, hatchcoverless, multi-purpose vessel, DNV · GL new rule, model test, bilge system, green water

摘要： DNV·GL新规范对敞口多用途船总体设计给出了明确的规范要求,需要研究新规范的变化及其对敞口多用途船总体设计的影响,用以指导后续研发设计。新规范的变化包括敞口耐波性模型试验时的最不利谱峰周期、船舶纵倾、船舶初稳性高,以及货舱进水后的完整稳性。该文以13 000载重吨敞口多用途船为例,分析新规范对总纵强度和舱底排水系统的影响,对比3型敞口多用途船的耐波性模型试验,总结出了减少甲板上浪的措施。由于货舱进水高度要求的降低,船体总纵弯矩和剪力下降明显,可以进一步节省船体结构钢材。新规范提高了货舱舱底排水系统的冗余度,不仅舱底泵需要冗余,舱底管系也需要冗余且特殊强调为环形管系。减少上浪的最有效措施是将上层建筑布置在首部且上层建筑宽度达到船宽,或在船首设置一定宽度和高度的防浪罩或挡浪板以有效阻挡上浪。

关键词: 敞口, 无舱盖, 多用途船, DNV·GL新规范, 模型试验, 舱底系统, 甲板上浪