造船专业英语课文全部翻译

1、第一课(陈锦航)商船的存在是为了把货物安全、快速、经济地通过水路运输出去。因为地球的表面的大部分（大约 3/5）为水覆盖，这就使我们有理由相信，商船在未来的很多世纪将继续使用下去。船及船上的货物和成员能够反映国际生活的很多方面。国际航行的一些特点，如天气、气候变化，货物装卸设备的布置和国际法规将在下面介绍。船舶有各种各样的形式，它根据三个主要因素来完成其功能货物的种类，结构形式和使用的材料，以及营运的区域。现今，有三种主要类型的运输船型：杂货船、液货船和客船。杂货船总的讲是作为运输船，同时也有几种特殊的船型用于运输以单元为基础或单元化了的货物。例如：集装箱船、托盘货船和液装船。液货船为了适于运

2、输石油、石油产品和液化气等货物有着特殊的结构。客船包括通常意义上讲的固定航线的客船和渡船。结构形式将影响货物运输，在某种程度上也影响船的内部特征。结构的主要形式指为了加强外板而进行的骨架布置形式，有三种结构形式：纵骨架式、横骨架式、混合骨架式。低碳钢、特种钢、铝和其它材料的运用也影响着船的特征。杂货船一般是横骨架式或混合骨架式，通常用的材料是低碳钢的型材和板材。大多数液货船采用纵骨架式或混合骨架式，大型船舶采用高强度钢。客轮有很大的上层建筑面积，采用轻金属材料和合金如铝来减轻上层建筑的重量。贸易范围、航行区域，可能遇到的最恶劣的气候，这些在一条船设计时就必须有所考虑。海船要求有几个液箱，用来装

3、载淡水和燃油。稳性和纵倾必须满足航行区域的天气要求。海船的结构强度抵抗波浪冲击的能力必须比内河船大很多。船在设计中和营运时最重要的是它的安全性，并把它放在首要位置，因此，船必须具有适航性。这同船的很多方面有联系，如：船在任何天气条件下必须保持一定的漂浮能力，船在破损时必须也保持有一定的漂浮能力，除非受到最严重的破损。在各种海况下保持稳定。有关适航性的一些结构和规则将在以后的章节中阐述。稳性和其它设计在由 W.Muckie 所著的轮机工程师船体结构中有详细讲解。只要在不同的贸易区有需求，船型就会继续发展下去。近年来，用来运输石油的超大型油轮有了很大发展，用来运送液化天然气、液化石油气这些大宗散货

4、液化气的船舶也有了进展。集装箱船和各种驳船被发展用来运输杂货。散货船和混装散货船（多用途散货船）也得到了相应发展。下面讨论几种主要的船型。五种船舶的外型特征、结构、布局、尺寸等要素将被讨论。（1）杂货船（2）液货船（3）散货船（4）集装箱船（5）客船还有其他船型和经过小的变化的船型存在，但是上面所选的这些被认为代表了当今世界上商船的主要部分(陈俊豪)1.1 杂货船杂货船是一个多面手，它可以在世界各地运输各种货物。它有尽可能大的开口及载货空间，配有货物装卸设备（图 1.1）。货物是通过甲板上称之为舱口的开口处进入货舱的。舱口足够大这样可以减少货物在船舱内的平移。舱口盖有木质的、有钢质的，在大多数

5、现代船舶中舱口盖在海上航行时盖住敞开的舱口。水密的舱口盖是盖在围板上的，围板装载舱口周围，并高出上甲板或露天甲板一段距离，以减小船在恶劣情况下进水的程度。货舱内设有一道或几道甲板，我们叫它为中间甲板。这样装卸货物更方便，并且可把货物分隔开，有利于提高船的稳性。各种各样的吊杆、绞车和甲板起重机被用来吊运货物。很多现代化的船都安装有甲板起重机，以减少货物吊运次数和对人力的要求。有时也安装重型吊杆负责一个或两个货舱。由于船不可能总是满载，因此船上布置了压载水舱。这样船就可以有适当的吃水深度来保证稳性，且保证了整个推进器浸深。艏艉尖舱有助于纵倾调整。双层底沿着船长方向布置并且被分成几个独立的液舱，有的

6、用来装燃油，有的用来装淡水。剩下的舱室在船空载或部分装载时装压载。船上还可能有深舱，它可以用来装液体货物和压载水。居住舱室和机舱通常设置在货舱和艉间舱舱壁之间。与机舱中置相比，当船部分装载时可改善船舶的纵倾，并且可以减少由于轴隧而损失的空间。杂货船的尺度在 2000T15000T 排水量之间，速度在 1218 节之间。冷藏杂货船为冷藏货设置冷藏设备，就能够运输容易变质的食品。冷藏船同普通杂货船相比变化很小。可安装不止一层中间甲板，所有的货舱都是隔绝的，以便减少热交换。货物是冰冻运输还是冷藏运输取决于货物本身的特性。通常冷藏船速度比杂货船快，可达 22 节，同时能乘载 12名旅客。1.2 液货船

7、液货船用来运输液态散货，最常见的船型是油轮。很多其它液体也用液货船运输，特殊结构的液货船还可以用来运输化学品，液化石油气，液化天然气等等。油轮的货舱被纵横舱壁分成很多独立的液舱（图 1.2）。油轮用泵卸货，泵安装在一个或多个泵舱里，泵舱位于液舱末端，或者有时也位于液舱中间。每个液舱都有通向泵管的吸口，液体货通过管道网被卸到甲板上，然后泵到岸上。油轮在货舱区没有双层底结构。艏艉尖舱用来装压载，通常还在船的中前部设有舷顶边舱装压载水。舷顶边舱只是压载舱，当船满载时，它就空着。在货舱区的末端设有很小的废油舱，在装载航行时，废油舱用来装被运输的油。压载航行时，废油舱被用来装清洗液舱产生的污物。甲板上，

8、从泵舱到船中的管簇卸载处，无论左舷还是右舷都可以看到大量的管道。吊管杆安装在左右舷靠近管簇处。现在的液货船，居住舱和机舱位于船舶尾部。目前油船的尺度范围极大，载重量从很小到 70 万吨的都有。航速在 12kn16kn 之间。(陈思强)Liquefied gas tankers 液化天然气油轮Liquefied gas tankers are used to carry, usually at low temperature, liquefied petroleum gas (LPG) or liquefied natural gas (LNG). 液化天然气油轮通常在较低的温度下携带液化石油气

9、(LPG)或液化天然气(LNG)。A separate inner tank is usually employed to contain the liquid and this tank is supported by the outer hull which has a double bottom. 一个单独的内箱通常是用来包含液体并且该油箱的外壳有双层底。LNG tankers carry methane and other paraffin products obtained as a by-product of petroleum drilling operations.液化天然气油

10、轮运输甲烷和其他石油钻井作业的副产品如石蜡产品。The gas is carried at atmospheric pressure and temperatures as low as 164 in tanks of special materials, which can accept the low temperature. 气体存储在能够承受气压和温度低至164的特殊材料制成的油箱中。The tanks used may be prismatic, cylindrical or spherical in shape and self-supporting or of membrane

11、construction. 油箱的形状可能是棱柱、圆柱或球面形状和自营或膜结构。The containing tank is separated from the hull by insulation which also acts as a secondary barrier in the event of leakage.储油箱被绝缘材料从船体中分离出来，这些绝缘体也作为泄露事件的第二道防线。LPG tankers carry propane, butane, propylene, etc., which are extracted from natural gas. 液化石油气油轮进行丙

12、烷、丁烷、丙烯等从天然气中提取的气体。The gases are carried either fully pressurized tank operates at 18 bar 1 bar = 105 Pa and ambient temperature, the fully refrigerated tank at 0.25 bar and 50. 气体进行要么储存在完全加压18吧的油箱中 (1吧= 105 Pa)或者环境温度完全在0.25吧和-50冷冻箱中。Separate containment tanks within the hull are used and are surrou

13、nded by insulation where low temperatures are employed. 船体内使用的油箱是独立的，在低温的环境中由绝缘材料包裹着。Tank shapes are either prismatic, spherical or cylindrical. Low temperature steels may be used on the hull where it acts as a secondary barrier. 油箱的形状是柱状、球形或圆柱形。低温钢可以使用它作为一个次要的船体上的障碍。 Displacement sizes for gas carr

14、iers range up to 60,000 tons, with speeds of 12-16 knots. 天然气运输船的排水量高达60000吨,，速度12到16节。1.3 Bulk Carriers 散货船 Bulk carriers are single-deck vessels which transport single-commodity cargoes such as grain, sugar and ores in bulk. 散货船是单层底船且只运输单一的大宗货物如谷物、糖和散装矿石。The cargo-carrying section of the ship is d

15、ivided into holds or tanks which may have any number of arrangements, depending upon the range of cargoes to be carried. 船舶货运部分根据货物的范围进行划分为任意数量的货仓或舱室。Combination carriers are bulk carriers designed for flexibility of operation and able to transport any one of several bulk cargoes on any one voyage,

16、e.g. ore or crude oil or dry bulk cargo.多用途的散货船被设计为操作灵活并且能够在任何一个航次运输任何散装货物,如矿石、原油或干散货货物。The general-purpose bulk carrier, in which usually the central hold section only is used for cargo. 通用的散货船,通常只中央部分用于装载货物。The partitioned tanks which surround it are used for ballast purposes either on ballast voy

17、ages or, in the case of the saddle tanks, to raise the ships center of gravity when a low density cargo is carried. 包围它的隔离舱通常是在压载航行中做压载目的或者是让承载舱提高船舶重心低密度货物。Some of the double-bottom tanks may be used for fuel oil and fresh water. 一些双层底的舱室可能被用于储存燃油和淡水。The saddle tanks also serve to shape the upper re

18、gion of the cargo hold and trim the cargo. 承载舱同样会影响货仓的顶部区域和削减货物量。Large hatchways are a feature of bulk carriers, since they reduce cargo-handling time during loading and unloading.散货船的一个特点就是有大的舱口，这是为了减少在装卸货物搬运的时间。An ore carrier has two longitudinal bulkheads which divide the cargo section into wing

19、tanks port and starboard, and the center hold which is used for ore. 矿砂船有两个纵向舱壁,将货物部分分为翼油舱左舷和右舷，以及装载矿砂的中间部分。The high double bottom is a feature of ore carriers. 双层底高是矿石运输的一个特征。On ballast voyages the wing tanks and double bottoms provide ballast capacity. 在压载航行过程中翼油舱和双层底提供了压载能力。On loaded voyages the

20、ore is carried in the central hold, and the high double bottom serves to raise the center of gravity of this very dense cargo. 在满载航行中，矿砂放在中央部位，而高双层底则为这高密度的货物提高重心。The vessels behaviour at sea is thus much improved. 船的航海性能因此得到了很大的提高。Two longitudinal bulkheads are employed to divide the ship into cente

21、r and wing tanks which are used for the carriage of oil cargoes. 两个纵向舱壁是用来将船划分为中心和用于石油货物翼油舱。When ore is carried, only the center tank section is used for cargo. 当运输矿砂的时候，只有中间的部分被用来运输货物。A double bottom is fitted beneath the center tank but is used only for water ballast. 双层底被安装在中部舱室的下面，并且只用来装压载水。The

22、bulkheads and hatches must be oiltight.舱壁和舱口必须是油密的。Large hatches are features of all bulk carriers, to facilitate rapid simple cargo handling. 大舱口是所有散货船的特点，这是为了有助于快速装卸简单的货物。A large proportion of bulk carriers do not carry cargo-handling equipment, because they trade between special terminals which h

23、ave particular equipment for loading and unloading bulk commodities. 大部分散货船不携带货物搬运设备,因为他们之间的贸易特殊终端具有特定大宗商品散货的装卸设备。The availability of cargo-handling gear does increase the flexibility of a vessel and for this reason it is sometimes fitted. 货物搬运装置的确增加了船舶的灵活性，因此有时船上也安装这种装置。Combination carriers handlin

24、g oil cargoes have their own cargo pumps, piping systems, etc., for discharging oil. 装卸油品的通用散货船有自己的货泵、管道系统等以便于卸油。Deadweight capacities range from small to 150,000 tons depending upon type of cargo, etc. Speeds are in the range of 12-16 knots.载重能力取决于货物的类型，范围从小型到150000吨。速度是在12至16节。(陈文驹)1.4 集装箱船集装箱船，顾名

25、思义，专门为运载集装箱所设计的。集装箱是一个可重复利用的截面为2435x2435mm 的箱子，其长度有 6055mm、9125mm 和 12190mm 几种。集装箱可用于绝大多数一般货物的装载，也有的装液货。同时也有制冷集装箱。集装箱的货舱区分为几个舱室，并且舱口的开口是舱的全宽与全长。集装箱在货舱搁置在特殊的骨架上并层层堆放起来。因而货物的卸载操作只是由货舱里货物的垂直移动组成。轻货集装箱有时也可堆放在舱口盖上。设置了特定的系绑装置，这层甲板上的货物在一定程度上弥补了下层甲板的舱容损失。为了保证船的横向强度，货舱之间被深腹板框架分开。集装箱的外侧部分有一个箱形的舷侧舱，它能保证结构上的纵向强

26、度。这些舷侧舱能用于装压载水，也可用来防止在卸运集装箱时所造成的横倾。设置双层底是为了增加纵向强度并提供了额外的压载空间。居住舱室与机舱通常设在尾部，以确保有最大的船长用于装卸。货物装卸装置几乎不设，因为它们航行在装有特定装卸装置的码头之间，可快速装卸。集装箱船的尺寸变化较大，以装100 箱到装 2000 箱不等或更多。作为专用运输工具，它们在设计时必须考虑到经济、快捷、大马力船速可高达 30 节，一些大船还设有三螺旋桨动力装置。1.5 客船客船，或现代的名称-客班船，是为了把旅客在风光和丽的日子里送往各名胜港口提供服务。乘客在旅行中希望船上是一流的服务设备和优雅的起居环境。客船的一个基本特征

27、是有大量的多层建筑。在多层甲板上设有露天休息室、舞厅、游泳池和供旅客散步的区域。大倾斜的飞剪形船首和与众不同的烟囱形状构成了船体美丽的型线。为了减少横摇，安装了平衡减摇装置减摇鳍；为增加操纵的灵活性，安装了艏侧推装置。大型的客班轮是不多的，排水量在 12000 吨的客班轮在目前流行。装载旅客能力为 600 人左右，航速在 22 节左右。介绍 一艘船能采用的外形是不可胜数的。一艘船可以看做是将乘客一直运送到外国目的地的优美的远航宾馆。竖立有导弹发射架的水面堡垒及甲板上铺盖有复杂管系的加长罐装原油运输轮。所有这些外部特点的描述都不能说明船舶系统是一个总的集合体船员和货物的安全性功能：自给

28、自足，适航，足够稳定。这是一个造船工程师设计船舶使必须记住的、能为以后讨论提供根据的观念，不仅涉及本章也贯穿全书。将船舶分成一些特定的种类来讨论造船工程是有好处的。本文的目的就是根据船舶物理支撑方式和设计目的来将它们分类。(陈燕虹) Ships Typed According to Means of Physical SupportThe mode of physical support by which vessels can be categorized assumes that the vessel is operating under designed conditionsShips

29、are designed to operate above，on，or below the surface of the sea，so the air-sea interface will be used as the reference datumBecause the nature of the physical environment is quite different for the three regions just mentioned，the physical characteristics of ships designed to operate in those regio

30、ns can be diverse按照物理支撑方式而划分的船舶就船舶分类而言，物理支撑形式是基于船舶在设计情况下进行的假定。船舶设计成在水上、水面或者水下工作，因此气水交界面将用于参考数据。因为前面提到的三个区域的物理环境特性差异很大，设计成在这些区域工作的船舶的物理特性也不同。Aerostatic support There are two categories of vessels that are supported above the surface of the sea on a self-induced cushion of airThese relatively lightwei

31、ght vehicles are capable of high speeds，since air resistance is considerably less than water resistance，and the absence of contact with small waves combined with flexible seals reduces the effects of wave impact at high speedSuch vessels depend on lift fans to create a cushion of low-pressure air in

32、 an underbody chamber. This cushion of air must be sufficient to support the weight of the vehicle above the water surface The first type of vessel has flexible “skirts” that entirely surround the air cushion and enable the ship to rise completely above the sea surface. This is called an air cushion

33、 vehicle（ACV），and in a limited sense it is amphibiousThe other type of air-cushion craft has rigid side walls or thin hulls that extend below the surface of the water to reduce the amount of air flow required to maintain the cushion pressure. This type is called a captured-air-bubble vehicle（CAB）It

34、requires less lift-fan power than an ACV，is more directionally stable，and can be propelled by water jets or supercavitating propellersIt is not amphibious，however，and has not yet achieved the popularity of the ACVs，which include passenger ferries，cross-channel automobile ferries，polar-exploration cr

35、aft，landing craft，and riverine warfare vessels静力支撑有两种类型船舶是靠前身产生的空气垫而支撑在海面之上的。这些相对较轻的船舶具有很高的航速，因为空气阻力远小于水阻力，还有的原因是在航行时不与海浪接触以及采用的柔性密封连接减少了海浪的冲击。这类船舶依靠鼓风机在船底部形成一个低压气垫。这个气垫必须足以支撑起水上船舶的重量。第一种类型船的四周具有柔性的“裙”，在船底围成一个空气垫，使船能完全升离水面。这种船称为“气垫船”（ACV），再有些场合是两栖的。另外一种是具有刚性侧壁或薄壳的气垫船，侧壁伸到水面下，维持气垫压力所需的空气流量就降低了。这种类型的船

36、称为束缚气泡减阻船（CAB）。这种船所需的升力风机功率要小于气垫船的，方向稳定性也更好，并可以由喷水装置或者超空泡螺旋桨推进。此类船非两栖，并且还没有达到像空气船那样推广，如旅客渡船、海峡汽车渡船、极地考察船、登陆艇及内河船。Hydrodynamic supportThere are also two types of vessels that depend on dynamic support generated by relatively rapid forward motion of specially designed hydrodynamic shapes either on or

37、beneath the surface of the waterA principle of physics states that any moving object that can produce an unsymmetrical flow pattern generates a lift force perpendicular to the direction of motionJust as an airplane with（airfoil）produces lift when moving through the air，a hydrofoil，located beneath th

38、e surface and attached by means of a surface piercing strut，can dynamically support a vessels hull above the waterPlaning hulls are hull form characterized by relatively flat bottoms and shallow V-sections（especially forward of amidships）that produce partial to nearly full dynamic support for light

39、displacement vessels and small craft at higher speeds. Planing craft are generally restricted in size and displacement because of the required power-to-weight ratio and the structural stresses associated with traveling at high speed in wavesMost planing craft are also restricted to operations in rea

40、sonably calm water，although some“deep V”hull forms are capable of operation in rough water水动力支撑依靠水动力支撑的船也只有两种类型。水动力是靠专门设计的水动力板在水面下做快速相对运动而产生的。一个物理原理表明任何带来不对称流体的运动物体都会在垂直于运动的方向上产生一个升力。正像具有机翼的飞机在空气中运动能产生升力一样，通过一个穿过水面的支柱而固定在水下的木翼，其水动力可以支撑一般船舶离开水面。滑行船体的特点是具有相对平坦的底部和浅V型剖面（特别是在船中前），高速航行时在局部可以为小排水量船和小型船提供足

41、够的水动力支撑。滑行艇的尺寸与排水量一般都受限制，因为功率重量比和在波浪中航行产生的结构应力大小都有要求。大多数滑行艇都要求在静水中航行，尽管某些深V型船体具有在波浪中航行的能力。(段礼倍/冯宝财)Hydrostatic support Finally，there is the oldest and most reliable type of support，hydrostatic supportAll ships，最后，有最古老和最可靠的类型的支持，支持所有船舶静水，boats，and primitive watercraft up to the twentieth century have

42、 depended upon the easily attained 和原始的船舶达第二十世纪都依赖于容易获得水的浮力来操作。buoyant force of water for their operation.This hydrostatic support，commonly recognized as flotation，call be explained by a这种液体静压支承，公认的浮选，可以由一个基本的物理定律解释说，fundamental physical law that the ancient philosopher-mathematician Archimedes defi

43、ned in the 在第二世纪古代哲学家、数学家阿基米德定义指出，second century BCArchimedesPrinciple states that a body immersed in a liquid is buoyed up浸没在液体中的身体的力等于被取代的液体的重量。（or acted upon）by a force equal to the weight of the liquid displacedThis principle applies to all这一原理适用于所有的船浮动（或淹没）在水盐和新鲜。vessels that float（or submerge）

44、in watersalt or freshAnd from this statement the name of the从这一声明在类船舶的名称来源； ships in the category are derived；they are generally called displacement hulls 他们一般称为排水型船体。Although this ship type is very familiar，its subcategories warrant special discussionFor虽然该型船是非常熟悉的，它的子类需要特别讨论。 example，in some vesse

45、ls reasonably high speed must be combined with the ability to carry light例如，在某些船相当高的速度必须结合进行轻货物规划船体特性来进行修改，cargo or to move more comfortably in rough water than a planing hullHigh-speed planning hull以产生一个船体或船体的能力，使船更合适。 characteristics can be modified to produce a semidisplacement hull or semiplanin

46、g hull. These 这些妥协的工艺，compromise craft，of course not as fast as full-planing hulls but faster than conventional 当然不一样快但比常规位移全滑行艇船体更快，displacement hulls，must have more power and less weight than the latterSuch types are要比后者有更多的力量和重量小。 obviously the result of “tradeoffs”这种类型的结果明显“折衷”。The example cited

47、 above lies between clear-cut physically defined categoriesit is not a 上面提到的明确的物理定义的类别，good example of a variation of a true displacement-type shipThe latter must be recognized它不是一个真正的排水变化类型船舶的一个很好的例子之间是例子。primarily as a displacement vessel，and its variations depend primarily on the distribution of后

48、者必须承认的是排水的容器，buoyant volumethe extent of the depth and breadth of the hull below the water和它的变化主要取决于浮力体积船体的水下的深度和广度上的分布。The most ubiquitous type of displacement ship can be generally classified as the common排水船舶最普遍的类型一般可分为共同的载体，海船。carrier，a seagoing vesselIt may be employed for passenger service，lig

49、ht cargo-carrying，fishing它可用于客运服务，轻型载货，捕鱼的拖网，by trawling，or for hundreds of other tasks that do not require exceptional capacity，speed，或其他的任务，不需要特殊的能力，速度，或其他特殊性能。submergence，or other special performanceIt is the most common and easily recognizable type of 它是最常见的容易辨认的船型，与适合的排水，速度适中，中等大的长度，和中度的能力。ship

50、，with moderate displacement，moderate speeds，moderate to large lengths，and moderate 中等大的长度，和中度的能力。capacitiesIt usually embodies the maximum in cruising range and seaworthinessIt is the “ship它通常体现最大的巡航范围和适航性。for all seasons”It is the standard to which all other ship classifications in the displacement

51、 它是“四季船”。它是标准的，在排水类的所有其他船舶分类可称。category may be referredThe closest relative to this standard vessel，which plays a crucial role not only in world最近的相对于这个标准船，它起着至关重要的作用commerce but in the survival of the industrial world as well，is the bulk oil carrier，the tanker，不仅在世界贸易而在工业世界的生存一样，是散装油轮，油轮，或者超级油轮。or

52、supertankerThese terminologies are common but unspecific，and in this discussion they are 这些术语常见但非特异性，并讨论他们是不够的，inadequate，for what was called a supertanker several years ago is today not a supertankerThe 几年前油轮在今天不是一个超级油轮。industry itself has created a far more explicit nomenclatureBased upon the inde

53、x of 100,000 tons该行业本身也创造了一个更明确的命名法。oil cargo capacity, the size categories are LCC(Large Crude Carrier). VICC(Very Large Crude 根据原油100000吨的货物的能力指数，大小类别的LCC（大型油轮）。Carrier), and ULCC(Ultra Large Crude Carrier). Any tanker greater than 100,000 but less than VICC（巨型油轮），和超大型油轮（超大型油轮）。200,000 tons is a L

54、CC, those between 200,000 and 400,000 tons are VLCCs, and those over 任何油轮大于100000但小于200000吨的LCC，那些200000至400000吨的巨型油轮，400,000 tons are ULCCs. The current necessity for these designations becomes clear when we和超过400000吨ulccs。这些名称目前的必要性变得清晰时，realize that before 1956 there were no tankers larger than 5

55、0,000 tons, and not until the early我们意识到在1956之前没有超过50000吨的油轮，sixties were any ships built larger than 100,000 tons. In 1968 the first ship over 300,000 tons was直到60年代早期进行的任何船舶建造超过100000吨。 1968超过300000吨的第一艘船。built. With their bulk and enormous capacity (four football fields can be placed end to end o

56、n one他们的体积和巨大的容量（四足球场可以放置的端到端的一座），of their decks),these ships are designed and built to be profit-makers, enormously long, wide, and 这些船的设计和建造的是利润，deep carrying thousands of tons of crude oil per voyage at the least cost. Few of these elephantine巨大的长，宽，深承载成千上万吨原油每航次以最小的成本。tankers have more than one

57、propeller shaft or rudder. Their navigation bridges are nearly one 这些巨大的船有一个以上的螺旋桨轴、舵。他们的导航桥一英里的近四分之一，quarter of a mile from their bows. Their top service speed is so low that a voyage from an Arabian他们的服务速度很低，一次由一个阿拉伯石油港口， oil port to a European destination normally takes two months.一个欧洲目的地通常需要两个月。Such vessels belong to a category of displacement ship that has a great range of buoyant这些船只属于一类排水船，有一个很大的范围内的浮力的支持。supportThey have a very large and disproportionate hull volume below the s