1、UNIT FOUR HULL CONSTRUCTION单元四 船体结构LESSON SEVEN1、generalA ship is something like a grand 宏伟的mansion大厦 floating on water and with a number of“floors地板，层”called decks.Among them is the upper deck that is the upmost continuous deck from bow船首 to stern；another continuous deck under the upper deck is ref
2、erred to as the lower deck.;Above the upper deck there are also a few other decks，they are the compass指南针、罗经 deck on which navigating instruments are arranged，the navigating deck where the wheelhouse驾驶室 is situated,the boat deck on which life-boats are fixed，and the accommodation住处 deck where the li
3、ving quarters生活区 for passengers and crew are located.In virtue优点 of the characteristics of hull construction,the construction above the upper deck is usually called superstructure上层建筑 while that under the upper deck is defined as main hull.For the purpose of reasonable合理的 arrangement and full utiliz
4、ation利用 of the inside space,hull is not only cut into some tiers层 by different decks,but separated into various sorts of compartments，spaces and cabins as well by“walls”called bulkheads隔壁，舱壁.The number of bulkheads depends u p o n s e a k e e p i n g 适 航 的 performances and service requirements，with
5、a mininum of three to four transversal bulkheads 横隔舱壁in the main hull.Main hull,by its different positions,will be separated into bow section,midship section and stern section.As usual,each section consists of bottom，side，deck and bulkhead and so on.Up till now至此，we have offered you a general descri
6、ption concerning the formation of hull.however，if you want to learn more of the hull construction，then you must go into the details of primary structures主要构件 of hull.2.Framing System骨架形式Basically,there are two broad主要的 systems of framingthe transverse and the longitudinal systems.In the transverse s
7、ystem of framing,the closely紧密的 spaced frames run transversely inside the shell.These transverse frames are further supported by widely space longitudinal members.The longitudinal system of framing differs from the above in that the shell and bottom plating is supported by closely space（longitudinal
8、）members running fore and aft.These longitudinal members are then reinforced加强 by widely space transverse frames.The type of framing system used is related to与有关 the type of cargo carried.For example,tankers are always constructed with a longitudinal system since tremendous巨大的 transverse members are
9、 needed in this system to stiffen加强 the vessel transversely so as not to interfere干扰、妨碍 the carriage of liquids.Freighters carrying general cargo cannot use this system since these transverse members would impede阻止 the stowage堆放 of cargo.3.Frame肋骨The most important function of frames is to stiffen t
10、he shell plating and compel强迫 it to retain保持 its proper form against the pressure of the water outside.The shell plating alone is somewhat稍微 flexible柔软的，能变形的 and without the support of the frames，it would collapse倒塌、变形.The frames also transfer weights from the deck to the bottom structure,where they
11、 are neutralized 平衡、制约by the ship s buoyancy.Frames may be formed of a simple shape,or they may be built up of plate and angles角度.The simple shapes are used for side frames；built-up组合的 frames are found in the bottom structure.The deepened transverse frames across the bottom of the hull are known as
12、the frame floors肋板.4.Shell外板 One of the basic structures结构 in hull construction建筑 is the shell structure which ensures vessel float-ability.It is the water-tight shell structure that is subjected to承受 different external外部的 forces，such as the total longitudinal bend,water pressure,wave impact冲击,squee
13、ze挤压 of blocks of ice,etc.In the shell structure,each shell plating has its own designation名称.For example,the plating located at the ship bottom is called bottom plates，among which are keel plates龙骨板 that are a series of plating sited位于 at the centerline of hull.Bilge plates舭板 denote表示 the plating a
14、t the bending areas from bottom to side.And the plating distributed at both sides is termed as side plates.Among them are topside plates that are in connection with the upper deck.Shell plating stands抵抗 external forces of different magnitude大小 in the light of its various situations.Accordingly因此，the
15、 thickness of plates will vary with the force to be subjected and there s no doubt that,at some key zones,local strengthening局部加强 is inevitable不可避免的、必修的.endLESSON EIGHT1、Bottom and SideIn addition to shell structure，there are bottom structure，side structure，deck structure，bulk-head structure,bow and
16、 stern structure and superstructure（上层建筑）,too.Ship bottom will normally be in two different patterns式样、模式,single bottom and double bottom.The double bottom and the wing翅膀 tanks边舱 have the same function。The wing tanks are located at the sides of a ship on the top of the double bottom.Sometimes the tw
17、o tanks are joined in a U-shaped or L-shaped fashion样子、流行.The functions of the double bottom and the wing tanks are:A.To increase the transverse,and the longitudinal strength of the ship；B.Additional safety when the bottom is damaged or in case of collision碰撞；C.To store seawater(ballast water)so tha
18、t the propeller is below the water surface even when the ship has no cargo in the holds.This is also advantageous有利的 for the stability of the vessel；D.To store fuel;E.To compensate补偿 for uneven不均匀 loading.Both the wing tanks and the double bottom are,in fact,watertight compartments水密舱室。In the double
19、 bottom，the central stringer桁材 is a longitudinal member located at the centerline of bottom from bow to stern,which assures you of the total longitudinal strength of hull。Side girders梁 are also longitudmal members situated at both sides of the centerline of bottom,which mainly withstand抵挡 the longit
20、udmal bend.Floor plates肋板 play the part of chief transversal members at the bottom,which are subjected to water pressure and gravity of cargoes and equipment as well as local external forces。they shoulder肩、承担 the responsibility责任 of transversal and local strength of bottom.Besides,inner bottom longi
21、tudinal and inner bottom plates and the like will also be adopted for the bottom structures as well,an oil tank and a drinking water tank must be separated by an empty space,so-called cofferdam隔离舱。several piping systems run through the double bottom，such as piping for bilge water systems舱底水 or balla
22、st water压载水 systems。Side structures are subdivided再分、细分 into two models,i.e.the transversal framing and the longitudinal framing,as it were,the side structures port and starboard are two side walls of hull symmetrical对称的 to each other，and among the side structures leading第一的、最主要的 components成分、部件 are
23、 the frames that bear water presure and secure保护 the transversal and local strength of hull.2.Deck and bulkheadThe deck structure is made up of deck plates，beams横梁，deck girders，deck longitudinal，hatch trunks舱口围板，pillars柱子 and Other members,in dealing with the deck structure,one thing is very interes
24、ting,that is,the arc弧、拱形 from port to starboard is termed as camber梁拱 while that from bow to stern is called sheer脊弧.Next其次 comes the bulkhead structure，which may assume采取、呈现 the forms of either plain平的 plate with stiffeners or corrugated弄皱、成波纹状 plate，the former is composed of steel plates and stiff
25、eners while the latter is steel plates pressed into corrugated shape.Bulkheads（employed to prevent oil and water from leakage)are put as oil-tight or water-tight bulkheads respectively分别，各自,bulkheads arranged along the ship length are called longitudinal whereas然而 those along the ship width are name
26、d transversal bulkheads.The principal function of bulkheads is to separate the inner space of hull so as to guarantee保证 vessel flood-ability抗沉性 and keep fire hazard危险 and poisonous有毒的 gas from spreading蔓延,not to mention the strength concern.3.Fore ship In respect to关于 the bow structure and stern str
27、ucture,the former usually denotes表示 the zone from bow up to 0.15 times of the ship l e n g t h s t a r t i n g f r o m f o r e perpendicular to aft,while the latter indicates the zone after the bulkhead of aft peak尾尖仓，.The fore ship is the part of the ship between the stem首柱 and the collision or for
28、epeak bulkhead。the space in the front of the collision bulkhead is the forepeak.The forepeak tank is uaually used as a ballast tank。If the ship is not loaded,this is often filled with water to reduce the trim纵倾 at the stern.Often there is a wash bulkhead制荡舱壁 in the peak tanks.This improves upon the
29、rolling摇摆 behaviour行为 of the ship,by delaying movement of the ballast water when the tanks are not completely filled.On the top of the forepeak,right below the capstan绞盘 or anchor winch there are chain lockers锚链舱 for the storage of the anchor chains。above the weather deck on the foreship is the fore
30、castle首楼。on the forecastle is the windlass锚机 and other mooring系泊 equipment,also the foremast前桅.The fore-ship is subject to extra额外、附加 large forces and stress that are caused by:A:the pitching纵摇 of ship;B:the foreship moving in and out of the water（panting晃动 stresses)C:maintaining speed in heavy weat
31、her.D:ICETo compensate for补偿 these forces，The fore ship needs additional reinforcements加强 that sometimes partly extend to the back of ship。the bulb stem球鼻首 is added to reduce the wave resistance兴波阻力,the bow wave causes a resistance that has a negative消极的 influence on影响 the speed of the ship.The addi
32、tional bulb creates a wave，which extensively equalises平衡 the bow wave and thus positively influences the ships speed(only under the loaded condition)。it is most effective有效的 at a certain draught(loaded ship)，but not so ideal理想 in the case of an unloaded ship because the bulb will actually produce mo
33、re resistance.4.Aft shipThe most eye-catching引人注目的 spaces aft on most ships are the e n g i n e r o o m a n d t h e accommodation。besides,there can also be working places，storage facilities设备 and fuel or ballast tanks.The aft peak is the part of the ship that is enclosed by the aft peak bulkhead,the
34、 stern and the aft deck，the aft peak is the location场所 through which the main engine shaft runs.For support there are floors in the aft peak,the stern structure endures water pressure,vibration振动 resulting from propeller and wave impact stirred up激起 by propeller.5 Engine RoomThe engine room is a com
35、partment that spans横跨、跨度 the full width of many ships.In tankers and bulk carriers,however,often there are bunker tanks燃油舱 in the sides so that in those cases,the engine room does not span the complete width of the ship.The back and the front are provided with two water-tight bulkheads；the engine-ro
36、om bulkhead(fore)and,if the engine room is at the after end of the ship,the aft peak bulkhead(aft).The double bottom below the engine room is sometimes higher than other sections of double bottoms to accommodate the propeller shaft.When the double bottom is not higher,the engine foundation will be raised.
