Cantilever System Design of Jack-Up Drilling Unit

 

ZHANG Yu-fan, ZHAO Jian-ting

(Marine Design & Research Institute of China, Shanghai 200011, China)

 

Abstract: The cantilever system is the most important operation module of the jack-up drilling unit and the key element in the development and design of jack-up drilling units. Taking the SJ350 jack-up drilling unit project as the object, this paper analyzes the design characteristics of cantilever systems both at home and abroad, and carries out deep investigations into the operation mode, main dimension planning, structural form design and the skidding equipment of the cantilever system, thus to propose its main dimensions and combined load parameters, and determine the load chart of the cantilever.

Key words: Jack-up drilling unit; cantilever; skidding; combined load

 

 

 

Analytical Calculation of Cargo Tank Internal Pressure of

a Liquefied Gas Carrier

 

FU Xi-hua

（Rules and Technology Center, China Classification Society, Shanghai 200135, China）

 

Abstract: Based on the acceleration analysis method specified in IGC Code for internal pressure calculation, the geometry theory and vector theory of linear algebra have been used to deduce a method for cargo tank internal pressure calculation, so as to obtain the analytical expression of internal pressure on a specific point. Compared with the current iterative numerical method based on acceleration ellipse, the analytical method is more accurate and has higher computational efficiency. The analytical solution of internal pressure can be obtained through defining the acceleration vector and performing vector operation, in combination of the parametric equation of acceleration. Then the analytical solution of maximum internal pressure for every point along the cargo tank boundary is deduced. It is found through sample calculations that the analytical calculation has the advantages of better accuration, better efficiency and better stability. This study provides reference for the internal pressure calculation and liquid cargo tank design.

Key words:liquefied gas carrier; internal pressure; analytical calculation; acceleration ellipse; acceleration ellipsoid

 

 

 

Load and Boundary Setting Optimization Method for the Transportation Analysis of Heavy Deepwater Jacket

 

ZENG Fan-quan, TANG Wen-yong, YAN Hui-bin

(State Key Laboratory of Ocean Engineering, Shanghai Jiaotong University, Shanghai 200240, China)

 

Abstract: This paper discusses the basic principles, load and boundary setting method and some other problems concerning the towing analysis of a deepwater jacket based on an actual project, and proposes a high efficient calculation method. This method mainly considers the forces acting on the jacket that supports the components, and combines the vessel’s horizontal motions with the corresponding rotational motions, so as to reduce the load cases from the previous 512 to 64, or even 16 under certain conditions. The method is validated through calculations. Moreover, a more reasonable boundary condition is proposed according to the actual installation process of the jacket, which takes into account more comprehensive considerations. Meanwhile, a general procedure for the offshore transportation analysis is summarized for reference.

Key words:deep-water jacket; towage transportation; load treatment; SACS; MOSES

 

 

 

Cabin Environment Design for the Living Quarters of

the Offshore Nuclear Power Platform

 

LEI Ya-hong, GUO Jian, WU Chen-hui

(Wuhan Second Ship Design and Research Institute, Wuhan 430064, China)

 

Abstract: This study compares and analyzes the design of ship’s living quarter and the nuclear power plant in accordance with the environment requirements of the marine rules and the requirements of the nuclear power design criteria regarding living quarter design such as ventilation and noise control, and thus to propose the proper requirements for the cabin environment design of the offshore nuclear power platform. The designs of the platform’s ventilation and air-conditioning, vibration and noise reduction, color and luminous environment are elaborated, which provides meaningful reference for the development of the cabin environment design of the offshore nuclear power platform in China.

Key words:offshore nuclear power platform; cabin environment; ship; nuclear power plant

 

 

 

 

Application of a Novel Leg Mating Unit

 

RUAN Zhi-hao¹，ZHAO Qing-kai²，ZHANG Wan-li¹，WANG Wen-juan¹，LIU Deng-hui²

(1. NengWei (TianJin) Engineering Services Co., Ltd., Tianjin 300392, China；

2. Tianjin Branch, China National Offshore Oil (China) Co., Ltd., Tianjin 300452, China)

 

Abstract: Focusing on the characteristics and difficulties of two-barge floatover method, which are distinguished from the one-barge floatover method, a novel leg mating unit is designed to solve the problem of energy concentration in the leg region due to unsynchronized motions of the two barges, and the problem of the uncertain gravity center caused by dismantling of the abandoned platforms using two-barge floatover method. A 6000t platform in the Bohai Sea was taken as the objective to prove the advantages of the novel leg mating unit by numerical simulations. The design of the novel leg mating unit can also be used for the local retrofit of the existing ships to make the two-barge floatover operation more economic, reliable and safer.

Key words:leg mating unit; two-barge floatover method; energy concentration; uncertainty of gravity center; the Bohai Sea

 

 

 

Arrangement of Venting System

in the Oil Cargo Tank of Tankers

 

HE Cheng-neng，ZHAO Bo

（Shanghai Waigaoqiao shipbuilding Co., Ltd.,Shanghai 200137, China）

 

Abstract: According to the regulations of International Maritime Organization (IMO) and the requirements of classification societies, this paper introduces the functions and characteristics of the venting system for the cargo oil tank of tankers. An effective and reliable solution is proposed when the design method of venting systems is studied, which provides technical support for the proper design and arrangement of the ship’s venting system.

Key words:tanker; cargo tank venting; inerting; gas-freeing; purging

 

 

 

Design and Application of New Traction Mechanism for

Cable Laying Ship

 

MA Yun-jiao, GE Yang-yuan

（Nantong Liwei Machinery Co., Ltd., Nantong 226500, China）

 

Abstract: In order to increase the operation efficiency of cable laying ships and to reduce the operation cost, the traction mechanism for cable laying ship is designed. This new type of traction mechanism works coordinately with traction winch, deck storage-cable winch, cabin storage-cable winch, anchor boat winch, cable-replacing device and guide pulley set, so as to tow and move the ship for cable laying. The working process and composition of the traction mechanism and the experimental validation shows that the traction mechanism plays an import role in increasing production efficiency, reducing operation cost, and improving the conventional method of moving the ship merely by anchoring in shallow waters and offshore operations.

Key words: traction winch; deck storage-cable winch; cabin storage-cable winch; anchor boat winch

 

 

 

Design of Power Distribution System for

Container Ships with RCP Notation

 

CHEN Jun-jie，XIA Jun，ZHOU Yi-long

（Marine Design and Research Institute of China, Shanghai 200011, China）

 

Abstract: This paper elaborates the electrical design requirements for container ships with the Refrigerated Container Stowage Positions (RCP) notation and analyzes the influence of RCP notation on the electrical design. Based on the comparison between a small reefer container ship with RCP notation and another one without the notation, the design solution that meets the requirements of classification societies is explained from the aspects of the power distribution system design, the capacity calculation and selection of power generator and isolation transformer, the centralized control of reefer container power supply, and the alerting system design of the reefer container system. An optimized solution which is more economical and more convenient to apply has been proposed. It will provide reference for the power distribution system design of other container ships with RCP notation.

Key words:reefer container; RCP notation; isolated transformer; excitation

 

 

 

 

Evaluation Method for Ergonomics Simulation of

Complex Ship Building Process

 

CAI Qian-ya，SHAN Xiao-fen，ZENG Zhen-zhen，ZHANG Hong-wei，ZHU Ming-hua

(Jiangnan Institute of Technology, Jiangnan Shipyard (Group) Co., Ltd., Shanghai 201913, China)

 

Abstract: As there is not verification method for ergonomic feasibility in the complex ship building process, design alternating and optimizing need a long time period, and the quality of scheme design greatly depends on the personal experience, the situations such as poor accessibility to work place, tiny work space, blind operation, fatigue operation and bad working environment, etc. frequently occur in the working site. This study proposes an evaluation method of ergonomics simulation for the complex ship building process and establishes the evaluation index on the basis of the application of ergonomics in the automobile and aerospace industries. The liquid tank hoisting of a liquefied gas carrier is taken as the example of ergonomics simulation evaluation, where the potential problems of liquid tank hoisting process are exposed in advance to help designer avoid design mistakes, reduce costs for R&D and manufacture, and improve production efficiency.

Key words:ship building; complex process; ergonomics simulation; evaluation method; evaluation index

 

 

 

Investigation on the Cause of Secondary H₂S and

Selection of Casing Material for Bohai Oilfield

 

WANG Xiao-peng^1,2, ZHANG Yu-chen¹, ZHANG Lei¹,

LIU Hai-long¹, YUE Ming¹, YIN Qi-shuai³

（1. Tianjin Branch of CNOOC Ltd., Tianjin 300459, China; 

2. National Major Laboratory of Marine Exploitation in High Efficiency, Tianjin 300459, China;

3. China University of Petroleum, Beijing 102249, China)

 

Abstract: As the yearly increased concentration of associated H₂S in Bohai Oilfield leads to higher requirements on casing material selection, this paper investigates the origin of H₂S and the selection of casing material. The H₂S concentration distribution characteristics are analyzed according to the sampling result, and the Sulfate Reducing Bacteria (SRB) enrichment and activity tests are performed by using the equipment including bacteria-free operating board, constant temperature incubator and autoclave. The time-dependent weightlessness function method is used to recommend the casing material for Bohai Oilfield based on the hanging piece experiment data and software check result. The result shows that H₂S in Bohai Oilfield is generated by SRB and appears as secondary H₂S, whose concentration is positively correlated to the development time of the oilfield. The temperature for the optimal growth of SRB is between 50~60℃, and pH value is around 7.5. Casing material of 3Cr has a long-term corrosion rate of 0.075mm/a in the Bohai Oilfield environment. The result of comprehensive strength check shows that 3Cr casing material can meet the requirements on Bohai Oilfield development.

Key words:Bohai Oilfield; corrosion; secondary H₂S; sulfate reducing bacteria; casing material selection

 

 

 

Application of Mechanics in Design and Installation of

Ship Propulsion Shaft

 

WU You-qi, LIU Jian-feng, CHEN Jian-guo, WANG Zhang-jian

(Shanghai Waigaoqiao Shipbuilding Co., Ltd., Shanghai 200137, China)

 

Abstract: The application of mechanics in marine engineering is introduced. Taking the alignment calculation and installation of the ship propulsion shafting system as the example, this paper elaborates both the establishment of the calculation model and the method for evaluation of the calculation result and checking of the shafting installation status. It is demonstrated that mechanics has important application prospect in shipbuilding technologies.

Key words:mechanics; propulsion shafting; mechanical model; calculation analysis; evaluation

 

 

 

Numerical Simulation of Containment Performance and

 Shape Optimization of Float Oil Boom

 

YANG Hao-tian, ZHANG Chuan

(China Harbour Engineering Co., Ltd., Beijing 100027, China)

 

Abstract: Oil containment boom is a simple and effective tool to prevent spilled oil from spreading, to reduce the area of spilled oil and to assist oil recycling. The FLOW3D software is used to simulate the oil containment process of oil boom under the actions of waves and current, so as to analyze the influence of different boom skirt shape on the oil containment performance. The result shows that the oil containing ability of the boom can be significantly changed with the change of boom skirt shape, which provides a preliminary plan for the optimization of the oil boom performance.

Key words:spilled oil at sea; floating oil boom; performance optimization; numerical simulation

 

 

 

 

Design and Implementation of Ship Data Fusion Layer

 

CAI Lu，QIAN Huai-yu，FU Ze-nan

（Shanghai Tresin Information Technology Company Ltd., Shanghai 201114, China）

 

Abstract: Data fusion is a key problem that shipbuilding enterprises must solve in improving design and production capacity and in realizing total quality control in the era of intelligent manufacturing. The establishment and effective implementation of data fusion layer can help ensure high efficiency and real economy of product development and production process. This paper discusses the major problems of data fusion currently existed in the industry according to the characteristics of data fusion activities in China’s shipbuilding industry and its challenges, and proposes an information framework for the deep integration of informatization and industrialization. An example of the system model in operation is introduced based on the actual implementation of a project in some domestic shipyards.

Key words:deep integration of informatization and industrialization; data technology; intelligent manufacturing