海洋救助拖船救助功能与配置研究

海洋救助拖船是对海上遇险人员和船舶实施有效救助的专用船舶.为对接我国海洋战略发展需求,要适应在深远海大风浪恶劣海况条件下对海上遇险人员和船舶的有效救助.针对海洋救助拖船适应深远海救助需求的基本功能设置,就船舶救助和人命救生的拖曳救助作业、对外消防灭火、海面人命救生、海面搜救、获救人员救治及保障等主要设备及设施配置作技术探讨.     

救助船模拟器原型机关键技术研究

针对大风浪条件下救助船操纵训练的要求，有必要开发针对救助船的操纵模拟器。相比于传统的通用船舶模拟器，救助船模拟器原型机系统中引入六自由度平台运动系统，基于UDP协议传输船舶姿态数据实现实时体感模拟功能，可以模拟船舶在大风浪条件下剧烈摇动的操船环境，提高模拟训练的真实感。此外，系统中引入救助作业模拟模块的思想，可以更好地评估、训练船员在恶劣海况下配合其他救助人员完成救助任务的能力，提高执行海上救助任务的成功率与效率。     

救助船模拟器原型机关键技术研究

针对大风浪条件下救助船操纵训练的要求,有必要开发针对救助船的操纵模拟器。相比于传统的通用船舶模拟器,救助船模拟器原型机系统中引入六自由度平台运动系统,基于UDP协议传输船舶姿态数据实现实时体感模拟功能,可以模拟船舶在大风浪条件下剧烈摇动的操船环境,提高模拟训练的真实感。此外,系统中引入救助作业模拟模块的思想,可以更好地评估、训练船员在恶劣海况下配合其他救助人员完成救助任务的能力,提高执行海上救助任务的成功率与效率。     

谈风险决策技术在海上船舶救助中的运用

<正>随着我国经济、贸易的发展和海洋开发战略的实施,海上运输、捕捞、石油勘探等日益发展,海上险情和事故频率不断增大,海上搜救也显得更加重要。海上搜救途径,不外直升飞机搜救和船舶搜救两种。东海海域,直升飞机搜救覆盖面不足且受天气条件限制,仍以船舶搜救为主。搜救船本身,通常处于恶劣且多变的气象和海况,     

JQA-7型减摇鳍转鳍故障实例

正0引言减摇鳍是船舶的新型减摇装置,在大风浪天气下能够改善船舶的稳定性,大大提高船舶的安全性和舒适性,为救助船舶在恶劣的海况下提供较为稳定的海上救助环境。本人对某救助船舶JQA-7型减摇鳍装置的转鳍故障进行分析,剖析故障原因,并结合实际情况加以排除,对故障处理方法提出建议。1 减摇鳍装置组成与控制原理1.1 基本组成减摇鳍装置主要由执行机构、鳍、液压机组和电控设备等组成,见图1。转鳍系统由电控系统、电液控制阀、油泵变量     

大风浪中运用救生吊篮进行人命救助的安全与风险分析

救生吊篮原本是一种供各类平台作业人员(物资)上下平台时使用的转运工具。近年来随着在专业救助船上的配备,被越来越多的救助船长所接受并在大风浪恶劣海况下进行人命救助时所运用。运用这种救助方式时要充分考虑当时遇险船态势、遇险人员的状态、救助船长对当时海况下救助船舶操纵性能的掌控、靠船时机的把握、靠船方式的选择以及各方人员的配合情况。     

浅谈冬季船舶航行安全

冬季气候多变,海况恶劣,是灾害性事故多发阶段.冬季船舶在海上航行或多或少会遇到大风浪或恶劣天气的影响,与此同时,若船舶采取的安全措施不当、船员操作失误、机械设备故障、船体结构失常、货物积载绑扎不稳妥等,很可能引发船舶碰撞、进水、货物移动、倾覆、船毁人亡等重大恶性事故.     

组建海上搜救社会应急船舶的迫切性

海上救助，任重道远；快速有效，人命关天。为了更好地集合社会船舶积极参与海上人命救助工作，快速及时有效地就近调动社会搜救资源参与海上搜救，对海上搜救基点进行合理布局调整，弥补台州搜救责任区搜救力量配置严重不足的现状。台州海事局根据辖区实际情况，于今年7月份组建了社会力量应急待命船舶和数据库，建立了搜救贴补机制，调动了社会力量参与海上搜救的积极性，较好地利用了社会搜救资源为台州海上搜救行动服务。     

防止大风浪对船员造成伤害

船舶在海上航行,气象变化反复无常,时而风平浪静,时而大浪滔天。当恶劣海况来临之际,船员们要高度警惕,它不仅直接影响船舶的安全航行,也有可能会直接伤害到船员的生命。一、几起事故回放近年来由于大风浪对船员造成伤害的事故屡有发生,这些惨痛的教训告诫我们,安全生产人人有责,安全生产刻骨铭心。船舶在海上航航行行,气象变化反复复无常常,时时而风平浪浪静,时而大浪滔天。当恶劣海况来临之际,船员们要高度警惕,它不仅直接影响船舶的安全航行,也有可能会     

气象海洋环境条件下救助船舶南海海上搜救风险评估

为保障救助船舶进行海上搜救时的自身安全,以交通运输部南海救助局常见的4类救助船舶为代表性船舶,考虑风、浪、流和能见度等主要影响因素,根据大量的专家问卷调查结果,基于模糊综合评价方法,建立救助船舶南海海上搜救风险评估模型,研究在不同气象海洋环境条件下,救助船舶在航行和实施救助过程中自身的风险程度.结果表明:该模型在南海的...     

Fine sediment deposits in shelf seas

From field observations it appears that the top layer of a shelf bottom in general exhibits an intricate geographical pattern of sediment formations. Sediments of different composition are confined in distinct regions. This contradicts the idea that current and wave forces stir up bottom sediment and disperse it in a random way over the shelf; the dispersal process is counteracted by sorting mechanisms. In this paper the bottom patterns of fine cohesive sediments are considered. A specific sorting mechanism is studied which may explain the patchy structure of fine sediment deposits. It is shown that fine sediments can be trapped in bottom deposits which contain a fine sediment fraction high enough to prevent pore water motion in the shelf bed. This mechanism opposes sediment dispersal away from existing deposits. It may also explain the formation or the preservation of mud patches, even in regions where the bottom shear stress is relatively high.     

Safer ships, cleaner seas

P&I clubs, as shipowners' organizations providing liability insurance for the same shipowners have a particularly vital role to play in exerting peer group pressure and raising standards of safety. Solutions are, however, never as simple as one might wish; this article explores the tensions and constraints within which P&I clubs operate, analyses where they are best equipped to support the Donaldson initiative and points out that there is an inherent conflict between liberal modern society and the desire for discipline on the high seas.     

Dynamic motions of planing vessels in head seas

The dynamic response of planing vessels in regular head seas is investigated numerically. Nonlinear time domain simulations were performed using a 2D + t theory (two-dimensional plus time dependent theory). A prismatic hull form was assumed. We employed a two-dimensional (2D) boundary element method to solve the initial boundary value problems in 2D cross planes, in which nonlinear free-surface conditions and exact body boundary conditions were satisfied. At each time step, the total force and moment on the hull could be obtained by using the sectional forces calculated in those 2D planes. Heave and pitch motions were then acquired by solving the equations for those motions. The calculated heave and pitch responses were compared with the experiments by Fridsma (A systematic study of the rough-water performance of planing boats. Davidson Laboratory Report R-1275, 1969) for two different Froude numbers. Three-dimensional (3D) corrections at the transom stern were applied to show the influence of the 3D effect at the stern on the numerical results. Ship motions were affected by the 3D corrections, especially near the resonance frequency, while the phase angles were slightly affected and the acceleration peaks at the bow near the resonance frequency were sensitive to the 3D corrections. Other error sources in the theoretical results are also mentioned.     

海浪动态仿真研究

对海面波浪的特点进行分析,提出了用合成波加细碎波的方法进行海浪的动态仿真,着重分析利用对合成波参数进行修正的方法来增强模拟风浪的真实效果,海浪模拟图例说明了该仿真方法可行。     

浅海海洋工程的结构型式

我国浅海地区蕴藏着丰富的石油天然气资源。但这一区域有着特殊的条件,如海底表层承载力差、淤泥层厚、冲刷严重。海洋环境条件差,海冰严重;潮差大、风暴潮频率高,潮间带涨潮时有水落潮时无水,所有这些决定了这一区域需用特定的开采方式。人工岛型式主要有砂石抛填式、沉箱圈闭式、桩基础围护式、格构式。砂石抛填式人工岛用得较多,这种类型的人工岛一般用在离岸近、水深浅的浅海区,结合进海路从岸边向海中推进。胜利油田有许多海上井场,就是采用这种小型人工岛建设的。沉箱圈闭式人工岛可建在水深较深的浅海。建造时先用各种类型的沉箱圈闭…     

Efficient calculation of slamming pressures on ships in irregular seas

An efficient method for calculation of the slamming pressures on ship hulls in irregular waves is presented and validated for a 290-m cruise ship. Nonlinear strip theory was used to calculate the ship–wave relative motions. The relative vertical and roll velocities for a slamming event were input to the slamming calculation program, which used a two-dimensional boundary element method (BEM) based on the generalized 2D Wagner formulation presented by Zhao et al. To improve the calculation efficiency, the method was divided into two separate steps. In the first step, the velocity potentials were calculated for unit relative velocities between the section and the water. In the next step, these precalculated velocity potentials were used together with the real relative velocities experienced in a seaway to calculate the slamming pressure and total slamming force on the section. This saved considerable computer time for slamming calculations in irregular waves, without significant loss of accuracy. The calculated slamming pressures on the bow flare of the cruise ship agreed quite well with the measured values, at least for time windows in which the calculated and experimental ship motions agreed well. A simplified method for calculation of the instantaneous peak pressure on each ship section in irregular waves is also presented. The method was used to identify slamming events to be analyzed with the more refined 2D BEM method, but comparisons with measured values indicate that the method may also be used for a quick quantitative assessment of the maximum slamming pressures.     

URANS analysis of a broaching event in irregular quartering seas

Ship motions in a high sea state can have adverse effects on controllability, cause loss of stability, and ultimately compromise the survivability of the ship. In a broaching event, the ship losses control, naturally turning broadside to the waves, causing a dangerous situation and possibly capsizing. Classical approaches to study broaching rely on costly experimental programs and/or time-domain potential or system-based simulation codes. In this paper the ability of Reynolds averaged Navier–Stokes (RANS) to simulate a broaching event in irregular waves is demonstrated, and the extensive information available is used to analyze the broaching process. The demonstration nature of this paper is stressed, as opposed to a validated study. Unsteady RANS (URANS) provides a model based on first principles to capture phenomena such as coupling between sway, yaw, and roll, roll damping, effects of complex waves on righting arm, rudders partially out of the water, etc. The computational fluid dynamics (CFD) method uses a single-phase level-set approach to model the free surface, and dynamic overset grids to resolve large-amplitude motions. Before evaluating irregular seas two regular wave cases are demonstrated, one causing broaching and one causing stable surf riding. A sea state 8 is imposed following an irregular Bretschneider spectrum, and an autopilot was implemented to control heading and speed with two different gains for the heading controller. It is concluded that the autopilot causes the ship to be in an adverse dynamic condition at the beginning of the broaching process, and thus is partially responsible for the occurrence of the broaching event.     

Dynamic stability in following seas: predictive and experimental approaches

This article presents work based on the development of a performance-based stability assessment method. It describes a numerical method used to determine the survival limit for a dynamic intact stability assessment procedure. The numerical method utilises a time-domain vessel motion program to assess the limit for a range of vertical centres of gravity (KG). The appropriateness of the numerical predictions was examined through comparison with model experiment results. Free-running model tests were conducted in regular following waves at discrete KGs. A comparison between the survival limits determined through the numerical and experimental methods is presented. The current International Maritime Organisation (IMO) stability criteria are also evaluated against the numerical and experimental dynamic performance-based stability assessment methods.     

中国海域潮汐预报软件Chinatide的应用

对中国海域潮汐预报软件Chinatide的理论基础、使用方法进行了简介;使用现场实测资料对Chinatide软件预报结果进行了对比验证;指出了应用Chinatide软件预报潮汐应该注意的问题。对于海岸河口潮流数学模型来说,Chinatide是一个很好的提供开边界条件的软件。     

还江河以奔流到海之势

“黄河之水天上来,奔流到海不复回。”千百年来,李白这气势磅礴的诗句被广为流传。在古人眼里,江河奔流不息汇入大海是其生命活力的体现。然而,近50年来,全国七大流域的江河上筑起了八万多座水坝。在我们自认为已驯服了江河,正可尽收防洪、发电、灌溉、航运诸方之利时,黄河断流了,辽河断流了,海河断流了,滦河断流了,汾河也断流了,往日汹涌澎湃地江河失去了奔流入海的气势。江河孕育了人类文明,没有了江河的奔腾,人类文明也将面临困境。