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Myboatplans 518 Boat Plans

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Weight of hull structure

According to ref. 4, the weight of the hull structure for an ACV, Ws can be written as Based on data from some SES designed and built in China, the weight of the hull structure can be estimated by the following equation 11 where W is the weight of the hull structure (kg), L the length of the hull structure (m), Fs the design speed (knots), Bs the cushion beam (m), H the cushion depth (m) and K a coefficient, which can be taken as

Welding and Cutting Processes used in Shipbuilding

Initially welding was used in ships as a means of repairing various metal parts. During the First World War various authorities connected with shipbuilding, including Lloyd's Register, undertook research into welding and in some cases prototype welded structures were built. However, riveting remained the predominant method employed for joining ship plates and sections until the time of the Second World War. During and after this war the use and development of welding for shipbuilding purposes was widespread, and welding has now totally replaced riveting. Other than some blacksmith work involving solid-phase welding, the welding processes employed in shipbuilding are of the fusion welding type. Fusion welding is achieved by means of a heat source which is intense enough to melt the edges of the material to be joined as it is traversed along the joint. Gas welding, arc welding, and resistance welding all provide heat sources of sufficient intensity to achieve fusion welds.

211 Computational fluid dynamics for hull design

CFD (computational fluid dynamics) is used increasingly to support model tests. For example, in Japan no ship is built that has not been previously analysed by CFD. CFD is often faster and cheaper than experiments and offers more insight into flow details, but its accuracy is still in many aspects insufficient, especially in predicting power requirements. This will remain so for some time. The 'numerical towing tank' in a strict sense is thus still far away. Instead, CFD is used for pre-selection of variants before testing and to study flow details to gain insight into how a ship hull can be improved. The most important methods in practice are panel methods for inviscid flows and 'Navier-Stokes' solvers for viscous flows. For hull lines design, in practice the applications are limited to the ship moving steadily ahead. This corresponds to a numerical simulation of the resistance or propulsion model test. Grids used in the computations must capture the ship geometry appropriately, but...

Mobile Agent Based Supply Chain Management In Shipbuilding Industry

Now China shipbuilding industry faces the following serious problems low productivity and long construction period. In order to cope with it, a mobile agent based supply chain management solution is provided. Firstly, summarizes the related research of supply chain management and intelligent agent and their application in shipbuilding industry. Secondly, a general commerce model which was developed by HAAS School of Business is used to design a shipbuilding supply chain management. Then implements a prototype which is based on IBM Aglet - a mobile Java agent development kit. The paper ends with some conclusions and suggestion for future research. Shipbuilding, Supply Chain Management, Mobile Agent Shipbuilding is a typical make-to-order manufacturing, which is very complex and complicate. In order to survive in the competitive global shipbuilding market, each shipyard tries its best to take measure to decrease the cost, enhance the quality and etc. For shipyard in China, the...

Shipyard Layout

Most shipyards are well established and were originally sited in a suitable location for building small ships with methods which have now been superseded. With the growth in ship sizes and the introduction of new building methods it has been recognized that a revised shipyard layout will be advantageous. Advantages to be gained, apart from the ability to construct larger vessels, are primarily, a uniform work load, a shorter ship build cycle, and economies in construction practices. These are obtained by having a layout that lends itself to an easy flow of materials from one productive process to another with elimination of bottlenecks. Other factors of course are involved in achieving a smooth production flow, but it is an advantage to start with a shop and equipment layout which is favourable. Very rarely has it been possible for the shipbuilder to select a new site and adopt an ideal layout. Normally the present site has to be used, and starting from the ideal it has been necessary...

Shipbuilding Steels

Steel for hull construction purposes is usually mild steel containing 0.15 per cent to 0.23 per cent carbon, and a reasonably high manganese content. Both sulphur and phosphorus in the mild steel are kept to a minimum (less than 0.05 per cent). Higher contents of both are detrimental to the welding properties of the steel, and cracks can develop during the rolling process if the sulphur content is high. Figure 5.1 Steel sections of shipbuilding Ship classification societies originally had varying specifications for steel but in 1959, the major societies agreed to standardize their requirements in order to reduce the required grades of steel to a minimum. There are now five different qualities of steel employed in merchant ship construction. These are graded A, B, C, D and E, Grade A being an ordinary mild steel to Lloyd's Register requirements and generally used in shipbuilding. Grade B is a better quality mild steel than Grade A and specified where thicker plates are required in the...

Honorary Advisory Committee

Rong-Sheng Wang, President, Chinese Society of Naval Architects and Marine Engineers Mr. Xiao-Jin Chen, President, China State Shipbuilding Corporation Mr. Shan-Xiang Hong, Vice Minister, Ministry of Communications Mr. Ping-Tao Huang, President, China Shipbuilding Industrial Corporation Mr. Zai-Kuan Jin, Vice President, China State Shipbuilding Corporation Mr. Ke-Jun Li, President, China Classification Society Mr. Zu-Yi Lin, President, China Institute of Navigation Prof. Dian-Zuo Wang, Vice President, Chinese Academy of Engineering Mr. Hui Wang, Vice President, China Shipbuilding Industrial Corporation Mr. Guang-Qin, Zhang, Vice President of Commission of Science, Technology and Industry for National Defence

Amphibious hovercraft or ACV

The amphibious hovercraft (Fig. 1.3) is supported totally by its air cushion, with an air curtain (high pressure jet) or a flexible skirt system around its periphery to seal the cushion air. These craft possess a shallow draft (or a negative draft of the hull structure itself) and amphibious characteristics. They are either passive (being towed by other equipment) or active, i.e. propelled by air propellers or fans. Some 'hybrid' craft have used surface stroking, balloon wheels, outboard motors and water jets to achieve different utility requirements.

Information Provided by Design

Almost all vessels will be built to the requirements of a classification society such as Lloyd's Register. The standard of classification specified will determine the structural scantlings and these will be taken out by the shipbuilder. The calculation of hull structural scantlings can be carried out by means of computer programs made available to the shipyard by the classification society. Owners may specify thicknesses and material requirements in excess of those required by classification societies and special structural features peculiar to the trade or owner's fleet may be asked for.

SES mine countermeasure craft Ses Mcm

Since the shock vibration of hull structure due to underwater mine explosions could be reduced by 60-80 compared with that on conventional craft, it was expected that hull structure weight could be reduced considerably. Additionally the underwater hydrodynamic pressure signature and acoustic field due to the motion of these ships were expected to be decreased dramatically because of the existence of the air cushion. SES were therefore projected to be very suitable for MCM because of these advantages. Meanwhile, the craft could provide a larger deck area than that on conventional ships and a more stable platform for continuing work on mine sweeping operations in rough seas. For this reason the US Navy began to develop the MCM SES in December 1982. The craft structure was made of GRP following the methods of Karlskronavarvet AB of Sweden, while a set of mine sweeping gear, and retractable crane with lift capability of 2.7t were to be mounted on the upper deck stern. Two diesels with...

Development to larger size

Similar to other high performance vehicles such as planing boats and hydrofoils, ACV SES also belong to the hydrodynamic support group of marine craft (c.f. static or buoyancy support). The difference between the ACV SES and planing hull and hydrofoil craft are that the ACV SES lift system operates at very low interface pressure, so that significant overload only leads to reduced craft speed, and does not seriously affect take off capability. One can also combine SES with other high performance vehicle characteristics to create a hybrid craft obtaining higher performance. There are two modes of operation for air cushion catamarans off cushion and on cushion modes. The SES with ordinary thin sidewalls has a large difference of speed between the two modes the off cushion speed is low at about 10-20 knots. In the case of an air cushion catamaran with thick sidewalls, it will operate as a high speed catamaran in the case of off There seems to be a misunderstanding on the seakeeping...

Military applications

In the smaller utility range, craft from Griffon and Slingsby deliver payload capacity between 1 and 5 tonnes suitable for amphibious coastguard patrol, which has proven effective in a number of European countries. The high speed, good seakeeping qualities and spacious deck and cabin areas suggest that SES, particularly the air cushion catamaran, could be used as patrol boats, anti-submarine vessels to join with PHM, and also as air cushion guided missile vessels. During the 1990s Norway has provided the technology leadership with the development of its fleet of MCM SES, followed by Fast Attack SES.

Market development from the beginning of the 80s to the present

Iran Hovercraft

Other transport systems such as hydrofoils, high-speed monohull passenger craft, high speed catamarans and long range buses and trains where appropriate. During the 1970s many companies had been set up in the UK and USA to develop business in constructing ACVs of all sizes from 2 seat recreation craft to large ferries. Many of these companies did not exist very long, often producing little more than design proposals. Those that were active found marketing difficult, as the public found the concept intriguing, and more of a 'solution looking for a problem'. Trial passenger services gained a reputation for unreliability, and short lived operation. Only the established services across the Solent and the Channel proved viable in the long term. HM-5 series, of which two craft were built for service in Hong Kong. Development beyond this point proved difficult, and it took Bell-Halter and Brodrene Aa to move the concept forward in the direction of Air Cushion catamarans in the early 1980s....

19 SES and ACV design

The Design Methodology section of this book begins with a review of the basic design requirements, including rules and regulations which have to be met. This is followed by a discussion on the estimating methods to determine principal dimensions. Once these have been estimated, the craft can be developed first by designing the lift system, the skirt, the hull structure and propulsion system. Main engines can then be formally selected, and after optimization of the main dimensions, consideration can be given to the craft systems and controls, and internal outfit.

Deck area and cabin volume

A 100 ton ACV SES can accommodate up to 300 passengers. This can also be achieved on a conventional monohull with the same displacement, unlike smaller craft. In order to accommodate twenty berths on a conventional planing hull, designers have to select a craft displacement of about 30 50t and power the craft by two sets of marine diesel 12V150 to achieve a speed of about 35 km h. In contrast, owing to the spacious cabin, an SES weighing only 20t can satisfy the requirement of berth arrangement and can reach a speed of up to 50 km h with the same main engines.

Wind Turbine Concept In Civil Engineering

Windmills have been used for at least 3000 years, mainly for grinding grain or pumping water, while in sailing ships the wind has been an essential source of power for even longer. From as early as the thirteenth century, horizontal-axis windmills were an integral part of the rural economy and only fell into disuse with the advent of cheap fossil-fuelled engines and then the spread of rural electrification. The use of windmills (or wind turbines) to generate electricity can be traced back to the late nineteenth century with the 12 kW DC windmill generator constructed by Brush in the USA and the research undertaken by LaCour in Denmark. However, for much of the twentieth century there was little interest in using wind energy other than for battery charging for remote dwellings and these low-power systems were quickly replaced once access to the electricity grid became available. One notable exception was the 1250 kW Smith-Putnam wind turbine constructed in the USA in 1941. This...

Classification Societies

The authorities with the most profound influence on shipbuilding, merchant ship design and ship safety are the classification societies. Among the most dominant are Lloyd's Register of Shipping, det Norske Veritas, the American Bureau of Shipping, Bureau Veritas, Registro Italiano, Germanische Lloyd and Nippon Kaiji Kyokai. These meet to discuss standards under the auspices of the International Association of Classification Societies (IACS). It is odd that the two most influential bodies in the shipbuilding and shipping industries should both derive their names from the same owner of a coffee shop, Edward Lloyd, at the end of the seventeenth century. Yet the two organizations

Shipping Industry In The Twentyfirst Century

At the same time ship's speed is increasing. At the moment, the designed speeds of post-panamax containership are between 25-27 knots. According to some reports, many shipyards and shipping companies are designing the ships whose capacity is 8000-12000 TEU, and the speed is up to 30 knots. Norasia has already operated a 1400 TEU ship with 25 knots speed Fastship has also planned to develop the 38 knots speed container ship in the transatlantic service. Their aim is not only to compete with other liners, but also to contend for the air freight market.

Concept development from the early 60s to the early 70s

Largest Hovercraft The World

Skirt damage from waves, subsequently hull structure damage, while in service Severe damage to hull structure from waves, craft sank shortly after these ideas were put forward the fuel crisis of 1974. Suddenly the world changed. With fuel costs now a major consideration, these very large ACV and SES concepts became uneconomic, and thus not attractive to the prospective operators, the ferry companies. It was only in the mid 1990s when fuel costs reduced again in relative terms and became more stable, that very high speed ferries became economically attractive. The vogue of the early 1990s had been catamarans in sizes now approaching that originally projected for SES. With this market acceptance, the next step will eventually be the re-introduction of air cushion technology to further increase speeds and work capacity above the practical limits for catamarans.

7Shipping industry will be more and more liberalised and the policy of free port will be pursued by quite a number of

After 40 years of development, the group, who owns and operates some 500 vessels in different sizes and types with total carrying capacity of more than 20mdwt, has successfully developed itself into a large-scaled shipping conglomerate, offering services in over 1200 ports in more than 150 countries or regions. Here, I would like to express my sincere gratitude to all of you in the field of shipbuilding and shipping industries. Thank you for your consistent understanding and support for the development of our businesses in the past 40 years

Winginground effect WIG and power augmented ram wing Parwig craft

Ground Effect Craft

Hovercraft Hydrofoil Monohull Catamaran Hovercraft Hydrofoil Monohull Catamaran ACV SES Catamaran SWATH WIG ACV SES Catamaran SWATH WIG The work of Sir Christopher Cockerell resulted in the first successful full scale hovercraft to be built in Europe, the Saunders Roe SR.N1, which crossed the English Channel for the first time on July 25, 1959. China began her own hovercraft research in 1957 in Harbin Shipbuilding Engineering Institute, which successfully operated their first open sea trials with a plenum chamber cushion hovercraft on the coast of Port Lu Shun in July 1959. The principal particulars for both the Chinese and British prototype hovercraft may be seen in Table 1.1. Harbin Shipbuilding Engineering Hovercraft have had their difficulties during development in the 60s and 70s, in the same way as most new transport concepts. The concept has now matured, and SES in particular are beginning to be developed at the size originally predicted by the early pioneers 1000 tonnes and...

Sidewall hovercraft or SES

This concept (Figs 1.4 and 1.5) reduces the flexible skirt to a seal at the bow and stern of a marine (non-amphibious) craft, using walls or hulls like a catamaran at the sides. The walls or hulls at both sides of the craft, and the bow stern seal installation, are designed to minimize the lift power.

33 Dimensions And Dimensional Relationships

The corresponding LIB ratios varied from between 6.2 for smaller ships of up to about 400 ft (120 m) to 7.6 for the biggest ships then being built. By 1975, when Fig. 3.7 was originally presented, ships of more than about 130 m in length were almost invariably being built with an LIB ratio of 6.5 ships of up to 30 m in length, such as fishing boats, usually had an LIB ratio of 4 whilst vessels whose length lay in the range between 30 and 130 m followed a linear interpolation pattern between LIB values of 4 and 6.5.

2 Classified Optimization

In the different design stages the optimization approach with different levels can be used for efficiently designing the ship hull lines. So many regressive results can be applied to mathematical models when optimization of ship hull dimensions is made. Such as BSRA Series (Wang and Huang, 1993), Series 60 (Wang, 1980), Series of Fishing Boats (Wang and Huang, 1977), ships with homogeneous hull and high speed (Wang and Xu, 1996) and so on are frequently used at the preliminary design stage. The objective function is the total resistance (coefficient) or the residual resistance (coefficient) and the optimized objects include principal dimensions and coefficients of hull form. 2.2 Optimization of Naked Hull Lines (Level 1) A calculation of thick dimensional boundary layer on ship hull with special velocity profiles and eddy viscosities (Wang and Long, 1989 Wang and Wan, 1989 and Wang and Long, 1992) and with the integral numerical method is employed to determine the viscous resistance....

32 Scope of application in ship design

The shipping company loses flexibility. Several small ships can service more frequently various routes harbours and will thus usually attract more cargo. It is also easier to respond to seasonal fluctuations. 4. Port duties increase with tonnage. A large ship calling on many harbours may have to pay more port dues than several smaller ships servicing the same harbours in various routes, thus calling each in fewer harbours. After the optimum size, speed, and number of ships has been determined along with some other specifications, the design engineer at the shipyard is usually tasked to perform an optimization of the main dimensions as a start of the design. Further stages of the design will involve local hull shape, e.g. design of the bulbous bow lines, structural design, etc. Optimization of structural details often involves only a few variables and rather exact functions. Soding (1977) presents as an example the weight optimization of a corrugated bulkhead. Other examples are found...

Study On The Process Technology For Line Heat Forming Of Hull Fabrication

Shipbuilding, Hull fabrication, Line heat forming, Optimum design, Simulation method. 1 INTRODUCTION The simulation method of line heat forming presented in this paper has been developed on the basis of the achievements of the first stage experimental research in China. This study has analyzed the practical conditions of China's shipbuilding industry, considered the characteristics of Chinese construction techniques, taken the advantages of longstanding co-operation between universities and shipyards, and made reference of the overseas research experience. The research has been divided into four stages. In the first stage, the essential local contraction values of the plate deformation, including contraction area and the maximum contraction length were studied, which are necessary for making complex developed curved surface from a plane plate. In the second stage, based on the processing data of ship plates, the mathematical model was established, which describes the relation between...

Modelbased Simulation For Container Loadingunloading

The emerging information and communication technologies of shipbuilding industrial environments are rapidly changing. To respond to the situation, a new paradigm has been matured with new concepts such as the concrete method. Especially, all the efforts are shown to be concentrated to realize the concept of Simulation Based Design(SBD) based on three dimensional Computer Aided Design(CAD) model. In Korea, SBD research has gained some interests in the commercial ship building industries and naval ships. Yet, the progress is far behind than the expectation. SBD technologies can be applied usefully to engineering parts such as virtual shipyard, marine accident simulation, marine safety, marine ergonomics, and so on.

Formal Safety Assessment Applied to Shipping Industry 311 Introduction

In 1993 a particular type of risk management framework in the ship safety regime was proposed by the UK to IMO, referred to as the Formal Safety Assessment (FSA). The FSA has been taken as a priority item on IMO Maritime Safety Committee's agenda in the conferences since then. IMO uses the FSA process for rulemaking and issued FSA interim guidelines in 1997 (IMO, 1997) and guidelines in 2001. Being a tool designed to assist maritime regulators, FSA is not intended for application to individual ships, but for use in a generic way for shipping in general. The main elements introduced by FSA are a formalized procedure, an audible process, communicated safety objectives, and priorities based on cost effectiveness. These have made the FSA a more rational risk assessment approach for the regulatory purposes in shipping industry.

Optimization in design

Most design problems may be formulated as follows determine a set of design variables (e.g. number of ships, individual ship size and speed in fleet optimization main dimensions and interior subdivision of ship scantlings of a construction characteristic values of pipes and pumps in a pipe net) subject to certain relations between and restrictions of these variables (e.g. by physical, technical, legal, economical laws). If more than one combination of design variables satisfies all these conditions, we would like to determine that combination of design variables which optimizes some measure of merit (e.g. weight, cost, or yield).

Ultimate Strength

In carrying out the limit state design of ship hulls, it is necessary to estimate the ultimate longitudinal strength of hull girders. Furthermore, in order to estimate oil spills due to tanker collisions and grounding, an investigation of the global dynamic behavior as well as the local plastic response of the individual ship hulls is required.

Derricks Masts and Rigging

When ordering a new ship the shipowner normally specifies the number, safe working load, position, and any special features of the cargo handling derricks to be fitted. The shipbuilder or an outside specialist consultant is then responsible for the detailed design of each derrick rig, together with the various fittings at the derricks and mast. Where patent derricks and masts are fitted the patentee may supply the drawings, etc., to the shipyard, who then build and erect these rigs. Masts, except some patent types, are the responsibility of the shipbuilders blocks, wire, and usually derrick booms being supplied by an outside manufacturer to the shipyard's specification.

184 Demarcations And Subdivisions Of Costs

Each shipyard has its own demarcation between materials, labour and overheads, and when making inter-firm cost comparisons it is essential to make sure the same demarcation applies or that suitable corrections are made. As well as the obvious items of steel, outfit and machinery, the materials cost includes the cost of work carried out by subcontractors working on the ship. This can introduce a difficulty when making inter-firm comparisons or even when comparing the performance of the same shipyard on two different contracts if the If a shipyard which normally does its own electrical or plumbing work uses a subcontractor or contract labour on a particular ship it is wise to synthesise cost records corrected to the shipyard's standard methods for future estimating use. It is worth noting that all material costs include labour costs and the distinction is whether or not these labour costs are, or are not, incurred in the shipyard. As an example, the steel used in a shipyard starts as...

Consideration Of Life Cycle Cost Of A Ship

In order to look all phases of a product life and to analyze the cost effectiveness elements, life cycle cost of a product has been widely studied. In case of a ship, it consists of fabrication phase in shipyard, such as design and fabrication, and maintenance phase in service, such as inspection, repair and painting. So far life cycle cost of a ship has been calculated by the summation of fabrication cost and maintenance cost by the end of her life. Although it is desirable to be able to estimate the life cycle cost of a ship, when she is born in a shipyard, the estimation is very difficult due to the variety of levels of fabrication and the maintenance. In this paper main items of fabrication cost and maintenance cost of a VLCC are analyzed focusing in hull structure part, based on the actual data from shipyards and ship owners and the relations between these costs are studied.

Cargo Access Handling and Restraint

To speed cargo handling and storage in modern ships apart from changes in ship design (Chapter 3), the introduction of mechanically handled hatch covers (Chapter 19) and improved lifting devices (Chapter 24), various patented or specially manufactured items may be brought into the shipyard and fitted to the ship by the shipbuilder. Some notable items which fall into this category are described in this chapter. These primarily relate to cargo access handling and restraint in ro-ro ships, container ships and vessels in which palletized cargo is carried.

1810 Approximate Cost Data

Obtaining cost and related data is not easy, as shipyards regard this information as something to be keep secret from their competitors. In spite of this the author managed to persuade a few shipyards to give him information, having assured them that this would be presented in a form which whilst providing useful data for making approximate cost estimates would at the same time preserve the confidentiality of the original data. The original intention was to give data in much the same form as is used in traditional shipyard cost estimating methods labour manhours and rates per manhour plus costs for materials used, each with some appropriate estimating parameter. It quickly became apparent however that the shipyards supplying the data all had different practices in relation to work for which in-house labour (manhours) was used and that for which they employed sub-contractors (material). Items for which shipyard practice was found to vary in this way included paintwork and joinerwork as...

27 Propellerinduced pressures

Due to the finite number of blades the pressure field of the propeller is unsteady if taken at a fixed point on the hull. The associated forces induce vibrations and noise. An upper limit for the maximum pressure amplitude that arises on the stern (usually directly above the propeller) is often part of the contract between shipyard and owner.

32 Experimental approach

Despite the ever increasing importance of numerical methods for ship hydrodynamics, model tests in towing tanks are still seen as an essential part in the design of a ship to predict (or validate) the power requirements in calm water which form a fundamental part of each contract between shipowner and shipyard.

155 Location Of The Principal Features

When the author started work in a shipyard in the 1940s, the engine room of most general cargo ships (and, for that matter, of most passenger ships) was located at or near amidships with two or three cargo holds forward and two aft. Tankers and small coasters were then exceptional in having their machinery aft and all the cargo space forward. The reason for having the machinery amidships at that date may have been partly tradition, but there was also the fact that in the size of ships then being built the space required for the large engines of the day could only be

26 Propeller design procedure

Estimate of delivered power for the ship PD ship hull form (lines plan) classification society often number of blades Z often diameter of propeller D Generally, the customer specifies within small margins what power PD has to be delivered at what speed Vs and what is the rpm of the (selected) main engine. While in theory such a combination may be impossible to realize, in practice the shipyard engineers (i.e. the customers) have sufficient experience to estimate a realistic power for a shipowner specified speed and rpm. The shipyard or another department in the model basin will specify a first proposal for the ship lines. Often, the customer will also already determine the number of blades for the propeller. A few simple rules gained from experience will guide this selection, e.g. if the engine has an even

142 Throughlife Costing

A contribution to the cost of dockyards required for maintenance and in particular to the cost of providing any new facilities such as a new dry dock or syncrolift which may be required if the existing facilities are inadequate. The first of these costs clearly provides a major incentive to keep a new design within the scope of existing dockyard facilities unless the improvement in performance obtained by going outside these is so significant as to justify this expenditure as for example in the change from Polaris to Trident submarines, where a step change in capability justified very major expenditure on new base In a typical modern frigate the cost of the combat systems may amount to between 35 and 40 of the total unit production cost and, in addition, very large sums will have been spent on the development of weapon and sensor prototypes. The development time for these will often be greater than that required to design and build the ship, which raises an important question for a...

712 Some Deadly and Severe Chemical Accidents 7121 Five Hundred and Seventy Six Die in Texas City Disaster3

Shortly after 8 AM, a longshoremen smelled smoke. No one knows what started the fire, but it was speculated that it was caused by a discarded cigarette on the ship in disregard of No Smoking signs posted on the wharf. The fire didn't cause much alarm there were no warnings about the explosive potential of ammonium nitrate - the dockyard workers thought it was inert. The longshoreman, who spotted the smoke, alerted his coworkers who moved several fertilizer bags and found some flames between the cargo and the hull. They tossed a jug of drinking water on the fire, and sprayed it with a fire extinguisher. The flames just got worse. Some of the crew members started hauling boxes of the small arms ammunition out of hold No. 5. The men fighting the fire in the No. 4 hold called for a hose line, but before they could use it, the ship's captain. Charles de Guillebon, intervened. Water would ruin the cargo, he said. The captain instructed his men to close the hatch to the No. 4 hold, cover it...

Floating Production Storage and Offloading Vessels

Many oil tankers have been converted to FPSOs and FSUs but there is an increasing trend to new design and build contracts for such vessels. The basic hull construction is similar to that for conventional tankers but there are arrangements and structural features peculiar to these vessels. The vessels are moored using a turret system forward which allows the hull to weathervane into the wind and waves to reduce dynamic loading on the hull girder. However, because the waves will be coming mainly towards the bow for the whole of its life the hull girder will experience greater fatigue problems than would be the case for a conventional tanker. The conventional tanker carries little in the way of loading on its main deck whereas an FPSO is fitted with a substantial oil production facility, which can weigh in excess of 20000 tons. This loading needs to be transferred into the hull structure which means that vertical structural components are more complex and substantial than those of a...

Nondestructive Testing

Of these five methods, the dye penetrant and magnetic particle tests have a small application in ship hull construction, being used for examining for surface cracks in stern frames and other castings. Visual, radiographic, and ultrasonic examinations are considered in more detail, as they are in common use.

Hovercraft weight terms [4

W4a electric power generator, switching, lighting, load centres, panels, cables ( W4) W4b communication and control communication (internal, external) and navigation equipment, military electronic computers, displays ( W4) W2 5 outfit and furnishing hull fittings including skirt system, marine hardware, ladders, furnishing, boats and rafts, life jackets, storages, lockers, painting, deck covering, hull isolation, insulation, commissioning equipment, radiation shielding Wl + W5).

156 Power transmission

There is often a trade-off between reduced distance and introduction of gearboxes in an SES for main propulsion engines, particularly for propeller-driven craft due to the narrow sidehull width. Where a reduction gear is needed anyway, this is not a particular problem. The design of smaller SES is also challenged by the vertical CG if engines have to be located above the sidehulls. It is common practice therefore to widen the hull towards amidships to accommodate engines within the hull depth. Water-jet systems require a significant keel width to optimize flush inlet design. This eases design of hull lines to accommodate engines immediately forward of the jet units.

5 Cfd Solver For Wave Drag Representation

Consider a ship advancing along a straight path, with constant speed U, in calm water of effectively infinite depth and lateral extent. The x axis is taken along the path of the ship and points toward the ship bow, the z axis is vertical and points upward, and the mean free surface is the plane z 0. Non-dimensional coordinates (x, y, 2) and velocities (u, v, w) are defined in terms of a characteristic length L (taken as the length of the center hull for a wave cancellation multihull ship) and the ship speed U. The wave drag Cw is evaluated using the Havelock formula The present wave cancellation multihull ship (see Wilson et. al. (1993) and Yang et. al. (2000)) consists of one main center hull centered at (0, 0, 0) and two identical outer hulls centered at (a, b, 0). In the first step of the optimal design process, the wave drag for each individual hull is evaluated using Eqns. 1-2, and the center hull and the outer hull are optimized independently for the purpose of minimizing the...

Modifying The Manoeuvring Performance

By and large the hull design of both a surface ship and a submarine is dictated by considerations other than manoeuvring. If model tests show a need to change the manoeuvring performance this would normally be achieved by modifying the areas and positions of the control surfaces and skegs.

Rational Design Criteria And Their Application To Hull Form Optimisation Of Floating Systems In Random Seas

Efficient design of new floating systems requires more and more numerical tools to develop structures with excellent motion behaviour in briefer time spans. The paper presents a fully automated numerical procedure for optimum adjustment of shapes to environmental conditions. Rational design criteria based on short and long-term wave statistics are introduced and utilized as objective function in the optimisation process. Nonlinear programming algorithms vary the form parameters of the design and find a minimum of the objective function within a few iterations. The resulting hull shapes are characterized by minimized wave loads and motions. Optimization of a semisubmersible illustrates the efficiency of the proposed procedure. Offshore operation of floating systems must cope with rough and hostile seas. Designs with favourable motion behaviour yield economic advantages avoiding restrained operation or weather induced downtime. Therefore, detailed performance analysis and optimization...

Useful range of the calculation

Where E is the elastic modulus on the normal direction (tf m2), I the section moment of inertia of the hull structure (m4) - this only includes the section moment of inertia of the main hull structure in the case of no strong superstructure, otherwise it must include the section of inertia of the superstructure. D is the displacement of craft (t) and L the craft length (m).

111 The design process

Initial determination of principal dimensions and key design parameters is the core of overall craft design. We will introduce here a methodology for this using a number of relationships which have been arrived at by successful experience. Once these initial data have been defined, the vehicle general arrangement, initial performance estimation, power plant selection and design of lift systems, skirt, propulsor and hull structure can be started.

Horizontal arrangement of fan without volute

This is an arrangement such as used for the BHC SR.N4 and SR.N6. The key requirement of such an arrangement is that the corridor from the air duct has to be roomy not only in the tangential direction, but also in the radial direction. All stiffeners or frames, pipes, cables, etc. have to be arranged far from the outlet. Although these fans are without a volute to diffuse air progressively into the cushion, the streamline is diffused freely in an intermediate plenum chamber formed by the craft buoyancy tank and hull structure. Experiments prove that this system can give high air duct efficiency due to the low air velocities.

Vibration characteristics and damping

A diesel main engine is the largest individual mass installed in an SES or ACV. In larger craft it can weigh as much as 30 to 401. While larger modern engines with 12-20 cylinders are well balanced, the vibration energy is still significant. Diesel engines are stiff structures, due to the high internal forces developed. Mounting direct to the structure of an ACV or SES will require careful analysis of the local supporting structure to determine its natural frequency and harmonics and response to the engine vibration energy spectrum (see Chapter 14). A resilient mounted engine will also require this type of analysis, with the additional parameter of the resilient mount damping response applied to the engine excitation. Resilient mounts assist to isolate noise transmission from diesel (or gasoline) engines in a metal hull structure. GRP does not transmit noise so efficiently, while foam sandwich panels act as noise attenuators.

Extended segment Fig 713e

This a relatively stiff skirt system for small utility and recreational craft in the size range 200-2000 kg. It does not respond greatly to waves and obstacles, except by deflection of individual segments. Segment width follows the same rule as for those attached to a loop, except that the height is now to the attachment at the craft gunwale, width being 20-25 of this total depth. Since the segments are 80-90 hull structure depth, they are generally quite wide and the air escape area is large in the segment delta region. Relatively high cushion flow is therefore required. This is not a problem for recreational craft, which do not have to meet the efficiency requirements of a commercial ACV.

Determination of external forces

Structural design should start with assessment of the quasi-static trim and equilibrium of forces at maximum speed. Designers normally estimate the external loads while the ACV SES runs in the required sea state at maximum cushion-borne speed. From the point of view of strength calculation, the estimation of such loads is critical. The distribution of wave-impacting load in longitudinal and transverse directions can be determined by empirical methods, using data from model tests or previously constructed craft and thus the dynamic bending moment acting on the craft can also be determined in a similar way to the method used for the strength calculation of planing hulls 90 . In order to determine external loads accurately, a great deal of model and full-scale ship experiments, similar to those on planing hulls, have to be carried out. So far such data are limited the main reference to which one can refer for information is the calculation method for determining external loads in the...

4 High Speed Craft Comparison

The trimaran model resistance results have been utilised for a comparison with the equivalent catamaran and monohull ships using the results obtained from previous model tests (Brizzolara et al. 1998 Cassella et al. 1998). Fig. 8 and fig. 9 show the residuary resistance to displacement ratios and the total full scale resistances respectively. Model data have been analised by ITTC'57 friction line. From the figures we can note the different trend for the curve relative to the monohull. It must be noted that this vessel presents an hard-chine hull whereas the catamaran and the trimaran have round bilge hull forms. It can be supposed that, at the higher Froude numbers the monohull is subjected to some hydrodynamic lift. From fig 8 a relevantly lower residuary resistance is highlighted for the trimaran, on the contrary the monohull definitely presents the higher resistance. Due to the effects of different waterline lenghts and wetted surfaces, smaller differences among the values can be...

Putting into service as specified in Harmonised Directives

Recreational craft Means 'any boat of any type, regardless of the means of propulsion, from 2.5 to 24 m hull length, measured according to the appropriate harmonised standards intended for sports and leisure purposes'. The fact that the same boat could well be used for charter and or for recreational boating training does not prevent it from being covered by this Directive when it is placed on the market for recreational purposes.

6 Prediction Of The Trial Performance

The final catamaran ship model with the designed foil system was manufactured and shown in Figure 3. Detail model tests were carried out with this final ship model. Figure 4 shows the catamaran ship model test in 60 knots with the hydrofoil system. It is clearly visible in Figure 4 that ship hull is properly lifted up above the free-surface with the desired dynamic trim. Figure 3 Catamaran Ship Model Figure 4 Catamaran Ship Model Test Figure 3 Catamaran Ship Model Figure 4 Catamaran Ship Model Test

5 Hydrofoil System Design

Hydrofoil system for large-size foil catamaran ships are mainly consisted of forward foil, aft foil, side struts which connect foil to ship hull and one or two center struts. Basically, hydrofoil system should be designed to satisfy the following two conditions in normal sailing In fact, it is very difficult to design the optimum hydrofoil system for foil catamaran ships. First of all. accurate estimation of the effect of free-surface on the hydrodynamic characteristics is very difficult. Interactions between ship hull and foil system, and between forward and aft foils are very complicated. Due to such complicated physical phenomena, no proper method has been practically existed to predict the performance characteristics or to determine characteristics of a foil system. Along the course of extended research works on the super-high-speed foil-catamaran ships, however, the authors have prepared a practically accurate method to predict the hydrodynamic characteristics or to determine...

The Design Of Trimaran Ships General Review And Practical Structural Analysis

In the last years, the applications of fast commercial transport at sea have aroused an increase of highspeed ships demand. More in particular mono-hull and catamaran passenger ships, in service on brief routs, are able to halve, respect to the conventional ships, the voyage times.

2 Selection Of Main Characteristics

Catamaran ships have many practical advantages such as large deck area, high stability, superior maneuverability, easy operation and maintenance, etc. Different from conventional mono hull ships, therefore, the container loading capacity(number of containers) for catamaran ships is not determined by deck area or stability, but by weight. The average weight of 7.5 tonnes per 20-foot container was selected in this study. To determine ship length and breadth, about 4,000 twenty-foot size containers were arranged on the deck. From this investigation, appropriate ranges of ship length(LPP) and breadth(BR) were obtained.

Froude Krilov hypothesis

Since there is a difference in density of 800 to 1 between the water in the waves and the pressurized air cushion, such an effect may be considered small. The skirt of an amphibious ACV is more likely to act as a damper rather than as a source of radiated wave energy. The hulls of an SES will be subject to the same inaccuracy as for a displacement ship, with the additional complication of the interaction of catamaran hulls.

Hiroomi Ozawa method [31

The theoretical calculation and test results of the wave-making drag of air cushion catamarans have been carried out by Hiroomi Ozawa 31 . Based on rewriting his equations found in 29 , the final equation for predicting total wave-making drag may be written as (when Fr 0.8) In conclusion, the methods for estimating sidewall drag introduced here are suitable for SES with sidewall displacement up to about 30 of craft total weight. Where a larger proportion of craft weight is borne by the sidewalls, the sidehull wave-making should be considered directly, rather than as a 'correction' to the cushion wave-making. Below 70 contribution to support from the air cushion, the beneficial effect of the cushion itself rapidly dies away, and so it is more likely that optimizing catamaran hulls will achieve the designer's requirements in the speed range to 40 knots. Above this speed, an air cushion supporting most of the craft weight is most likely to give the optimum design with minimum powering.

Trim and water surface deformation under the cushion

The starting point for determination of equilibrium is the centre of pressure of the cushion for an ACV and in addition the force vector which results from the hydrody-namic force acting on the hulls of an SES or through the skirt. This may be compared with the forces acting on the hull of a planing boat or catamaran.

Masts and Sampson Posts

Short lengths and welded in the shipyard. The short lengths may be tapered and are of different plate thickness to allow for the greater stresses experienced at the base of the mast. Where connections are made for fittings such as the gooseneck and a masthead span swivel, doubling or welded reinforcing pads may be provided. To obtain the necessary mast scantlings, excessive doubling or internal stiffeners are rarely found in modern practice, except where a heavier derrick than that for which the mast was originally designed is carried. Higher tensile steels are often used to advantage in mast construction, giving less weight high up in the ship and dispensing with the need for any form of support, without excessive scantlings.

Ship Drawing Offices and Loftwork

Shell Expansion Plan Ship

The ship drawing office is traditionally responsible for producing detailed working structural and general arrangement drawings for parts of the hull and outfit. Structural drawings prepared by the drawing office will be in accordance with Lloyd's or other classification rules and subject to their approval also owner's additional requirements and standard shipyard practices are incorporated in the drawings. General arrangements of all the accommodation and cargo spaces and stores are prepared, which allow for statutory requirements as well as shipowner's requirements and standards. Other outfit plans, piping arrangements, ventilation and air conditioning (which may often be done by an outside contractor), rigging arrangements, and furniture plans, etc., are also prepared. Since the late 1970s, developments in computer hardware based on microchip technology have made available to industry very powerful computer systems at moderate cost. This technology has led to a significant advance...

The IMO International Gas Carrier Code

The code covers damage limitations to cargo tanks and ship survival in the event of collision or grounding, ship arrangements for safety, cargo containment and handling, materials of construction, environmental controls, fire protection, use of cargo as fuel, etc. Of particular interest in the context of ship construction is the section on cargo containment which defines the basic cargo container types and indicates if a secondary barrier is required, i.e. a lining outside the cargo containment which protects the ships hull structure from the embrittling effect of the low temperature should cargo leak from the primary tank structure. The cargo containment types are described below. INTEGRAL TANKS Those tanks which form a structural part of the ships hull and are influenced in the same manner and by the same loads which stress the adjacent hull structure. These are used for the carriage of LPG at or near atmospheric conditions, butane for example, where no provision for thermal...

Single Bottom Structure

In smaller ships having single bottoms the vertical plate open floors are fitted at every frame space and are stiffened at their upper edge. A centre line girder is fitted and one side girder is fitted each side of the centre line where the beam is less than 10 m. Where the beam is between 10 and 17 m two side girders are fitted and if any bottom shell panel has a width to length ratio greater than four additional continuous or intercostal stiffeners are fitted. The continuous centre and intercostal side girders are stiffened at their upper edge and extend as far forward and aft as possible.

Schneekluth method for containerships

To isolate the influence of the main data and ratios on the hull steel weight, the construction and building method was kept as uniform as possible over the entire variation range. Checked using statistical investigations, this corresponds reasonably consistently to practical reality and the building method applied in shipyard. The following boundary conditions for the method result 1. Full scantling vessel with freeboard in open double-hull construction, i.e. with broad hatchways and longitudinal bulkheads below the longitudinal hatchway coamings. The upper section of the wing tank at a height of 2.4 m is assumed to be of higher strength steel HF 36 between engine room and forecastle. On ships over 200 m in length the floor of the gangway, which forms the upper part of the wing tank, also consists of high-tensile (HT) steel. While HT steel is rarely used in the upper decks of smaller ships except for the hatch coamings, in this weight estimation...

Za40 And Za40s Engines

Gate Charge Injection

Plunger seizures initially occurred on Z40 engines due to insufficient clearance (either through manufacturing with too small a clearance or reduction of clearance in heavy fuel service as a result of the tendency of the material used earlier to grow at higher temperature levels). An increased plunger clearance and a changeover to a new material specification for the plungers, supported by stricter quality control, proved to be design remedies. Operationally, shipyards and operators

Stem Construction Of Ship

On many conventional ships a stem bar, which is a solid round bar, is fitted from the keel to the waterline region, and a radiused plate is fitted above the waterline to form the upper part of the stem. This forms what is referred to as a 'soft nose' stem, which in the event of a collision will buckle under load, keeping the impact damage to a minimum. Older ships had solid bar stems which were riveted and of square section, and as the stem had no rake it could cause considerable damage on impact because of its rigidity. Small ships such as tugs and trawlers may still have a solid stem bar extending to the top of the bow, and some existing large passenger ships may have steel castings or forgings forming the lower part of the stem. A specially designed bow is required for ships assigned Ice Class AC notations and additional scantlings are required for the stems of ships assigned other ice classes (see Chapter 17).

Joining Ship Sections Afloat

Owing to the enormous increase in size of bulk carriers and tankers, shipyards with restricted facilities, berth size particularly, have examined various means of building these large ships in sections which are to be joined off the berth. In most cases the problem becomes one of joining the two hull sections afloat or in a dry-dock of sufficient size where available. Where the sections are to be joined afloat extremely accurate fit up of the sections is aided by the possibilities of ballasting the two ship halves. The two sections may then be pulled together by tackles and for the finer adjustments hydraulic cylinders may be used, extremely accurate optical instruments being employed to mark off the sections for alignment. One method adopted is that where a cofferdam is arranged in way of the joint, a caisson is brought

Fabrication Of Large Aluminium Panels By Mechanised Mig Welding

Chadburn and Salter, 'The Welding of Higher Tensile Shipbuilding Steels', The Naval Architect, January, 1974. 'Japanese Shipbuilding Processes (Automatic Vertical Electro-Gas Arc Welding)', Shipbuilding and Shipping Record, 26 May, 1966. Kallee, 'Application of Friction Stir Welding in the Shipbuilding Industry', Lightweight Construction Latest Developments 2000, Royal Institution of Naval Architects Publications. North and McNeill, 'The Trend to Mechanised Welding in Shipbuilding', The Naval Architect, July, 1973. Phillip, 'Shipyard Welding Processes for Hull Construction', R.I.N.A. Monographs (M7). 'The Use and Welding of Aluminium in Shipbuilding', Symposium, London, Institute of Welding, 1956. Turner, 'Report on Visits to Japanese Shipyards', Metal Construction and British Welding Journal, June, 1970. Turner, 'The Welding of High Tensile Steels Used in Shipbuilding', Parts 1 and 2, Metal Construction and British Welding Journal, October and November 1970. 'Welding in...

Medium speed enginesintroduction

Carbon Cutting Ring Cylinder Liner

New designs and upgraded versions of established models have maintained the dominance of medium speed four-stroke diesel engines in the propulsion of smaller ships as well as larger specialist tonnage such as cruise vessels, car passenger ferries and ro-ro freight carriers. The larger bore designs can also target the mainstream cargo ship propulsion market formed by bulk carriers, containerships and tankers, competing against low speed two-stroke machinery. The growth of the fast ferry sector has benefited those medium speed enginebuilders (notably Caterpillar and Ruston) who can offer designs with sufficiently high power weight and volume ratios, an ability to function reliably at full load for sustained periods, and attractive through-life operating costs. Medium speed engines further enjoy supremacy in the deepsea genset drive sector, challenged only in lower power installations by high speed four-stroke engines. A Japanese challenger in a medium speed arena traditionally dominated...

Nature and Forms of Corrosion

Atmospheric corrosion Protection against atmospheric corrosion is important during the construction of a ship, both on the building berth and in the shops. Serious rusting may occur where the relative humidity is above about 70 per cent the atmosphere in British shipyards is unfortunately sufficiently humid to permit atmospheric corrosion throughout most of the year. But even in humid atmospheres the rate of rusting is determined mainly by the pollution of the air through smoke and or sea salts.

Design Modification Of Vlcc With Wide Web Frame Space

R& D Team Daewoo Shipbuilding & Marine Engineering Co. 1 Ajoo, Koje, KyoungNam, Korea In the design of vessel, it is difficult to satisfy both aspects simultaneously, long-term operation life with minimum maintenance costs and structural design with the economic ship building costs. Many research activities have been carried out for the development of new VLCC which has the long-term operation life and simple maintenance faculty in line with economical structural design Park, et

15 ACV and SES development in China

The Harbin Shipbuilding Engineering Institute (HSEI) started to develop a new kind of water transport concept - the hovercraft with plenum chamber type air cushion -in 1957, and completed the first model craft in China with a length of 1.8 metres. The commercial SES type 'Jin Sah River' (Fig. 1.5) was completed in Shanghai Hu Dong Shipyard, and was delivered to Chong Cheng Shipping Company in April 1971. Three high speed Chinese manufactured diesels were installed for lift and propulsion. The craft could accommodate 70-80 passengers and operated at a speed of 57 km h. The craft has now been operated on Jin Sah River for many years. diesels as the main engines for this craft. The economy of modified craft 716-11 (Fig. 1.37) was improved significantly by this engine change. Meanwhile, the rigid sidewall hovercraft type WD-901 (Fig. 1.38) was designed as a water bus for shallow water, developed jointly by Shanghai Ship and Shipping Research Institute (SSSRI), the Communication Bureau of...

Cfdbased Parametric Study On The Smoke Behavior Of A Typical Merchant Ship

Daewoo Shipbuilding & Marine Engineering Co., Ltd., 1-Aju-Dong, Koje-City, Kyungnam, 656-714 Republic of Korea For last several years DSME (Daewoo Shipbuilding and Marine Eng. Co., Ltd.) has practiced numerous model tests and CFD analyses concerning the smoke exhaust performance of the funnel. Through these experiences, now DSME has a good knowledge of a flow around the funnel and especially, its ability of CFD analysis is on a fairly high level. But there is no standard to use properly in the funnel design. By the way, recently, owner's requirements for the model test or CFD analysis to guarantee the smoke exhaust performance are increasing and thus the related costs are increasing. Therefore, a proper method to estimate the smoke exhaust performance is highly required. The behavior of the smoke exhausted from ship funnel is important in relation to the onboard hazard such as pollution, high temperature, machinery malfunction and so on. And it strongly depends on the funnel and...

Elastic Center Method

In observing the inside of an airplane fuselage or seaplane hull one sees a large number of structural rings or closed frames. Some appear quite light and are essentially used to maintain the shape of the'body metal shell and to provide stabilizing supports for the longitudinal shell stringers. At points where large load concentrations are transferred between body and tail, wing power plant, landing gear, etc., relatively heavy frames will be observed. In hull construction, the bottom structural framing transfers the water pressure in landing to the bottom portion of the hull frames which in turn transfers the load to the hull shell.

92 Welding soldering and brazing

The integrity of a welded component, which has metallurgical continuity across the joint, is also characterised by properties such as pressure tightness, or heat and corrosion resistance. These properties have contributed to the rapid development, both technical and economic, in all fields including nuclear power, chemical engineering, bridge building, offshore engineering, shipbuilding, and the manufacture of automobiles, railway locomotives and rolling stock, aircraft engines, domestic appliances, and military hardware from small arms to main battle tanks.

Calm Water Experimental Research On Geosims Of High Speed Trimaran Hydrodynamic Characteristics And Modelship

Several comparisons among multihull and the monohull ships, on the basis of equivalent service capabilities, have highlighted the advantages of each hullform the catamaran is known to be very well adequate to the above mentioned service. form and position, the total resistance could be the same or even smaller in comparison with the equivalent catamaran or monohull.

Design Synthesis For Ships And Floating Systems

Optimization of a Wave Cancellation Multihull Ship Using CFD Tools C Vang, R. Lohner and O. Solo The Fine Optimization of Ship Hull Lines in Resistance Performance by Using CFD Approach Hull Form Design of a Passenger Catamaran for Operation in the Yellow Sea Region Conceptual Design of Very Large-Size Super-High-Speed Foil Catamaran Containership 105

Simulation Of Viscous Flow Of Modern Surface Ships Using The Finflo Rans Solver

To validate our approach, various types of ship geometry, such as the DTMB 5415 model, the KCS model, the HTC model and the tanker model, are used as the test cases with two turbulence models, the Baldwin-Lomax model and the Chien's low Reynolds number k-e model. The convergence performance and the effect of the grid density on the free-surface waves are investigated. The results obtained are compared well with the experimental data provided by the KRISO, the INSEAN, the shipyard and the HSVA. For the former two test cases, an improvement for the free-surface waves has been achieved as compared with our latest work (Li et al., 2000), which has been presented in the workshop held recently at Gothenburg (Larsson, et al., 2000). Without doubt, the studies from CFD groups of various countries represent the major advances in this area, although just a few CFD groups completed these two cases in this workshop.

16 SES and ACV developments in the 1990s

In 1984 85 a shipbuilder in Norway, Brodrene Aa, teamed up with a firm of Naval Architects, Cirrus, to design a large passenger SES, after being impressed with the performance of the US Navy's test craft SES200 when it performed a series of demonstrations in Europe for NATO. Their concept was a GRP hulled development similar in concept to the BH-110, with catamaran hulls and diesel engine power. Propulsion Other builders in Norway developed their own designs, initially for ferries, as a higher speed variant to their main product, the high speed catamaran. In 1986 the Norwegian Navy began a programme to develop an SES Mine counter measures vessel, again encouraged by the earlier US Navy Programme. After keen competition, a consortium of companies in Mandal, Southern Norway won the contract. Cirrus provided technical expertise for the cushion system. A total of nine craft were built and are in operation with the Royal Norwegian Navy. The commercial SES product development started by...

Study On Heat Transfer Between Gas Flame And Plate During Lineheating Process

Line heating process, which is one of the most characteristic works in the shipbuilding industry, is applied to the formation of curved hull plates. This work has not been carried out by the automatic operation, but by skilled workers. Recently the automatic operation has been strongly desired because of the decrease in skilled workers. In order to automate this process, heat transfer between flame and plate has to be evaluated theoretically. A methane gas is used as fuel gas. Table. 1 shows the pressure and the flux of methane, oxygen and NO. The heating power of this torch is much lower than that of line heating torches used in shipyards. A square mild steel plate with sides 500mm long and 16mm thickness is arranged horizontally and a torch with a circle shaped nozzle of 0.9mm diameter is positioned above the plate. The center of the plate is heated by a flame of premixed methane and oxygen. The distance Z between the nozzle and the plate is arranged to be 12,20 and 28mm. The...

15 United Stirling Engines

United Stirling A.B., was formed in 1968 by Forenade Fabriksverken (FFV) and Kockums Mekaniska Verkstads A. B. FFV is a defence-related industrial group owned by the Swedish government. Kockums is a large publicly-owned Swedish company having its main business in shipbuilding and the lumber industry.

Hotair Engine Competitions

Stirling Engine For Home Use

Many of these builders are also very interested in building practical engines of 100 to 800 W (1 8 to I hp) suitable for powering small skiffs or bicycles, perhaps on solid fuel. One builder who has already completed such a project is Morris Bomford < 1975), shown with his Stirling-powered boat in Fig. 20.8. I lis large-volume, slow-turning engine propels the skiff at 1.3 to 1.8 m s (3 to 4 mph). It is expected there will be much more amateur activity in this area, too, in the near future.

Plate and Section Machining

Line Bending Steel Plate

Plate profilers Where a plate is to be cut into one or more, or a series of complicated shapes, a profiling machine is employed. At present where these employ gas cutting, the machines are generally referred to as 'flame profilers'. All flame, or plasma-arc profilers have some form of automatic control, the sophistication of which may vary considerably the following methods of control are found in shipyards operator guides the follower around the template, or tracing head around the drawing profile. Profilers of this type have a limited application in shipbuilding, but might be used for cutting a batch of standard brackets, etc. (b) Some of the earlier flame profilers found in shipyards were controlled by 10 1 drawings prepared by loftsmen as indicated in Chapter 12. The control mechanism for the machine was located in a darkened booth within the plate machining sheds. A tracing head with photo-electric cell traversed the 1 10 scale drawing located on a viewing table, following the...

Surface effect ship development

Length to beam ratio and thicker sidewalls, such as those on the US Navy test SES XR-5 and the Soviet passenger SES model Gorkovchanin. The draft of these craft in off cushion condition is such that the 'wet deck' no longer enters the water to provide buoyancy. These concepts are more like a slender hulled catamaran when floating. 2. The craft was specified with medium operational speed, low fuel consumption and seakeeping quality not worse than that on an equivalent planing monohull, high speed catamaran or high speed displacement ship 5. Adopt thickened sidewalls. During off cushion operating mode, the twin hulls provide a large buoyancy similar to that on a catamaran, up to 100 of craft weight, and the clear distance between the wetted deck of craft and water surface was similar to that on catamaran, improving the manoeuvrability and performance of craft at low speed. The prototype BH-110 was launched in 1978, and was later purchased and modified in 1980 by the US Navy....

Loftwork Following Drawing Office

The mould loft in a shipyard was traditionally a large covered wooden floor area suitable for laying off ship details at full size. cad cam loftwork We have already seen that shipyard-installed computer systems are capable of fairing the lines full size and storing these as a 3-dimensional model. This stored information can be accessed by the

Criteria for the practical application of bulbous bows

For 0.29 < Fn < 0.32, lengthening the CWL of smaller ships reduces the power more than a bulbous bow corresponding to the CWL lengthening. However, a bulbous bow installed on ships with Fn > 0.26 reduces power more than lengthening the waterplane by the projecting length of the bulb. Figure 2.20 shows how far a normal bow (without bulb) must be lengthened by ALpp to save the same amount of power as a bulbous bow, where LB is the length of the bulb which projects beyond the perpendicular and ALpp is the power-equivalent lengthening of the normal form. On the upper boundary of the shaded area are located ships which have a high or too high CB in relation to Fn and vice versa. For Fn < 0.24 the equivalent increase in length is always less than the length of the bulbous bow. For Fn > 0.3, the bulb effect may not be achieved by lengthening. Thus determining an equivalent length is useful when deciding whether or not a bulbous bow is sensible.

Study On An Information System Of Damages Of Ship Structures

Recently, Computer Integrated Manufacturing System (CIMS) for ship building has been studied (for example Ship & Ocean Foundation 1989-94) and now the concept is practically applied in the design and manufacturing process in many shipyards. Furthermore, the concept of the life cycle support such as CALS concept is proposed in which not only the effectiveness of the design and manufacturing processes but also the effective operation and maintenance of ships are considered. For the effective maintenance of the ship structures, a new concept of an information system of damages of ship structures has been studied by the authors (Kawamura et al. 1998, 2000). In this paper, we firstly describe about the concept of the information system and about the object oriented data model for crack damages used in the system. Second, the prototype system constructed on an object oriented database on an engineering workstation is demonstrated. Thirdly, based on the proposed information system, a ship...

852Friction stir welding

It will soon be used for non-structural components in conventional commercial aircraft and is being actively considered for structural use. Friction stir welding has also been introduced into shipyards with great success and is being actively investigated for applications in the railway rolling stock and automotive industries. Although this development is relatively recent it has been enthusiastically adopted by the rail rolling stock manufacturers and a number of shipyards in addition to its use in the aerospace industry.

2speed Trial Analysis Procedure Of Isodis 15016

The analysis procedure of ISO DIS 15016 is divided into six steps. This analysis procedure is based on Taniguchi-Tamura's Method (Taniguchi etc., 1966). Various calculation methods of resistance increase due to the disturbances and the deviations are suggested to use at annex of ISO DIS 16016. In this guideline, it has described that the methods presented in the annexes are the latest one available today, other scientifically-based method including model tests may be adopted as agreed between shipyard and ship owner.

13 ACV and SES development in the former USSR

The principal design offices and shipyards for ACV and SES are all located in what has become the Russian Federation. Since 1993 the Russian government has pursued a policy of conversion of its military construction facilities into commercial ventures. The main shipyard which constructed ACYs for the Russian Navy is located on the river Neva, and is now called Almaz Shipbuilding Company. Almaz built two of the total 31 Gus class amphibious hovercraft (20.6 m, 27 tonnes) which were produced for the Russian Navy between 1969 and 1979. Three Gus can operate out of the Ivan Rogov class landing ships. Almaz shipyard also built two Utenok class (70t, 27 m, 65 knots) amphibious assault craft in 1982. Recently the Dolphin Design Bureau has redeveloped this design as a passenger ferry for 98 persons, marketed by the shipyard as the Utenok-D3. A commercial version of the Pomornik has also been prepared. The Russian Navy also has in service a group of inshore minesweeping ACVs which were...

35 Special cases of optimization

Conditions for series shipbuilding are different from those for single-ship designs. Some of the advantages of series shipbuilding can also be used in repeat ships. For a ship to be built varying only slightly in size and output from a basis ship, the question arises 'Should an existing design be modified or a new design developed ' The size can be changed by varying the parallel middlebody. The speed can be changed by changing the propulsion unit. The economic efficiency (e.g. yield) or the initial costs have to be examined for an optimum new design and for modification of an existing design. Efforts to reduce production costs by simplifying the construction process have given birth to several types of development. The normal procedure employed in cargo shipbuilding is to keep CB far higher than optimum for resistance. This increases the portion of the most easily manufactured parallel middlebody. For small ships 0.8-1.0 m

Notice to Shipowners Masters and Shipbuilders

Following the loss of the Lairdsfield, referred to in Notice M.627, the Court of Inquiry recommended that simplified stability information be provided. This simplified presentation of stability information has been adopted in a large number of small ships and is considered suitable for wider application in order to overcome the difficulties referred to in paragraph 1.

11 Hovercraft beginnings

Some planing craft and fast naval vessels reached this speed in the 1920s. They were able to do this because payload was not a key requirement, so that most of the carrying capacity could be devoted to power plant and fuel. Hydrodynamic resistance was the prime factor limiting their performance. A displacement ship moving at high speed through the water causes wavemaking drag in proportion to the square of its speed. This limits the maximum speed for which a ship may be designed, due to practical limitations for installed power. It is possible, however, to design ship forms using the surface planing principle to reduce wavemaking at higher speeds. Many planing boat designs have been built, though the power required for high speed has limited their size. Their application has mostly been for fast pleasure and racing craft, and for military vessels such as fast patrol boats. Planing vessels demonstrated the potential for increased speed, but slamming caused by wave encounter in a seaway...

Constant Propeller Torque

And bollard pull tests provided by the thruster manufacturer. These relations may later be modified during sea trials. However, as shown later, they are strongly influenced by the local water flow around the propeller blades, hull design, operational philosophy, vessel motion, waves, and water current. In conventional positioning systems, variations in these relations are not accounted for in the control system resulting in reduced positioning performance with respect to accuracy and response time. In addition, the variations may also lead to deterioration of performance and stability in the electrical power plant network, due to unintentional peaks or power drops caused by load fluctuations on the propeller shafts, as shown in Fig. 3.38. The unpredictable load variations force the operator to have more available power than necessary. This implies that the diesel generators will get more running hours at lower loads in average, which creates more tear, wear, and maintenance. This...

Energy And Environment Dimension In Ship Manufacturing Processes

The main issues of energy and environment associated with shipyards manufacturing processes are presented. The direct and indirect demands of energy in the shipbuilding industry are clarified. The Life Cycle Analysis (LCA) in ship production is addressed with particular emphasis on the methods commonly used to reduce energy consumption and relevant harmful environmental impacts. The holistic approach of LCA is briefly outlined. The importance of rationalization of materials used in shipbuilding and ship scrapping is stressed. The modern approach of Ship Design for Environment is highlighted. The paper is concluded by stressing the importance of introducing the relevant energy and environment courses into the educational programs of Naval Architecture and Marine Engineering departments. Shipbuilding, Energy, Environmental impacts, Pollution, Risk analysis, Life cycle analysis, Design for environment The shipbuilding and ship repair industries consume various types of energy for ship...

Criticism of the freeboard regulations

For small ships, the dependence of the freeboard on ship size results in smaller freeboards not only in absolute, but also in relative terms. Seen in relation to the ship size, however, the small ship is normally subjected to higher waves than the large ship. If the freeboard is considered as giving protection against flooding, the smaller ship should surely have relatively greater freeboard than the larger ship.

How To Have A Perfect Boating Experience

How To Have A Perfect Boating Experience

Lets start by identifying what exactly certain boats are. Sometimes the terminology can get lost on beginners, so well look at some of the most common boats and what theyre called. These boats are exactly what the name implies. They are meant to be used for fishing. Most fishing boats are powered by outboard motors, and many also have a trolling motor mounted on the bow. Bass boats can be made of aluminium or fibreglass.

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