Unit 24 Compass and Gyrocompass.doc

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1、Unit24 Compass and Gyro-compass罗经和陀螺罗经I The Magnetic Compassed Magnetism磁罗经和磁场The principle of the present day magnetic compass is no different from that of the compasses used by ancient mariners. It consists of a magnetized needle, or an array of needles, allowed to rotate in the horizontal plane.

2、The superiority of the present day compasses over ancient ones results from a better knowledge of the laws of magnetism which govern the behavior of the compass and from greater precision in construction.现代罗经使用的原则与过去海员所使用罗经的原则，没有什么不同。它包括一根磁针或者一列磁针，在水平面内旋转，现代罗经比古代罗经优越是由于对控制罗经的行为相关的磁学的规律有了更好的了解，还由于罗经制

3、造时有了更好的精确度。Any piece of metal on becoming magnetized will develop regions of concentrated magnetism called. Any such magnet will have at least two poles of opposite polarity. Magnetic force (flux) lines connect one pole of such a magnet with the other pole. The number of such lines per unit area rep

4、resents the intensity of the magnetic field in that area. If two such magnetic bars or magnets are placed close to each other, the like poles will repel each other and the unlike poles will attract each other. 任意一根金属被磁化，是磁学发展的集中领域。任意这样的磁体都会至少有磁性相反的两极。磁感线将这种磁体的一极与另一极连接起来。单位区域内磁感线的密集程度可以表现出该区域磁场的强度。如果

5、两条这样的磁铁或磁性物质被放置的很近，相同的极将互相排斥，不同的极将互相吸引。 Magnetism can be either permanent or induced. A bar having permanent magnetism will retain its magnetism when it is removed from the magnetizing field. A bar having induced magnetism will lose its magnetism when removed from the magnetizing field. Whether or n

6、ot a bar will retain its magnetism on removal from the magnetizing field will depend on the strength of that field, the degree of hardness of the iron (Retentively), and also upon the amount of physical stress applied to the bar while in the magnetizing field. The harder the iron, the more permanent

7、 will be the magnetism acquired. 磁性可以是永久性的，或者感应的。一根具有永久性磁性的磁铁当它从磁场中移出的时候将保持其磁性。一根具有感应磁性的磁铁当其从磁场中移出后将失去磁性。一根金属棒从磁场中移出后是否仍具有磁性取决于磁场的强度，铁的硬度（顽磁性）也取决于当其处于磁场中时时施加在其上的物理压力的大小。铁越是坚硬，它获得的磁性就越久。 II Terrestrial Magnetism地磁Consider the earth as a huge magnet surrounded by magnetic flux lines connecting its two

8、 magnetic poles. These magnetic poles are near, but not coincidental with, the earths geographic poles. Since the north seeking end of a compass needle is conventionally cared the north pole, or positive pole, it must therefore be attracted to a south pole, or negative pole. 把地球看作一个被连接其两极的磁场线所围绕着的巨大

9、的磁场。这些磁极与地球地理上的两极相接近却并不重合。一根罗经指针红色的一极通常被称为北极，或者阳极，它必定被南极或阴极相吸引。Since the magnetic poles of the earth do not coincide with the geographic poles, a compass needle in line with the earths magnetic field will not indicate true north, but magnetic north. The angular difference between the true meridian (

10、great circle connecting the geographic poles) and the magnetic meridian (direction of the lines of magnetic flux) is called variation. This variation has different values at different locations on the earth. These values of magnetic variation may be found on relevant chart, on pilot charts, and, on

11、the compass rose of navigational charts. The variation for most given areas undergoes an annual change, the amount of which is also noted on charts. 由于地球磁场的两极与地理的两极不完全重合，一根沿着地球磁场线的罗经指针将不会指向真正的北极，而是磁场的北极。这个在直子午线（过地理两极的大圆）与磁子午线（磁场线的指向）之间角度的差异称为地磁偏角。这个偏角在地球的不同地方有不同的值。地磁偏角的这些值会在相关的海图上，在引航员手，航运海图的罗经花上面可以

12、找到。对于大部分已经给出值的地区这个偏差角发生着年度变化，这种年度变化也同时在海图上会标出。 III Ships Magnetism船磁A ship under construction or major repair will acquire permanent magnetism due to hammering and jarring while sitting stationary in the earths magnetic field. After launching, the ship will lose some of this original magnetism as a

13、result of vibration and pounding in varying magnetic fields, and will eventually reach a more or less stable magnetic condition. The magnetism which remains is the permanent magnetism of the ship. 在建或者大修的船舶长久地停在地球磁场里由于锤击辗轧将获得永久的磁性。在开锚起泊后，由于在变化着的磁场里振动和重击将失去这种原来的磁性，同时最终或多或少达到磁场稳定状态。剩余的磁性就是船舶永久的磁性。 The

14、 fact that a ship has permanent magnetism does not mean that it cannot also acquire induced magnetism when placed in the earths magnetic field. The magnetism induced in any given piece of soft iron is a function of the field intensity, the alignment of the soft iron in that field, and the physical p

15、roperties and dimensions of the iron. This induced magnetism may add to, or subtract from, the permanent magnetism already present in the ship, depending on how the ship is aligned in the magnetic field. The softer the iron, the more readily it will be magnetized by the earths magnetic field, and th

16、e more readily it will give up its magnetism when removed from that field. 事实上一艘拥有永久磁性的船舶并不意味着当它置于地球磁场时不能同时获得感应磁性。任何所给的软铁的感应磁性是磁场强度，软铁在磁场中的位置，及软铁的物理特性和形状的大小共同作用的结果。这感应的磁性可能增加或者削弱船舶已经具有的永久磁性，这取决于船舶在磁场中的定位。越软的铁，被地球磁场磁化越容易，当它离开那片磁场区域时失去这种感应磁性也越容易。 The magnetism in the various structures of a ship, whic

17、h tends to change as a result of cruising, vibration, or aging, but which does not alter immediately so as to be properly termed induced magnetism, is called sub-permanent magnetism. This magnetism, at any instant, is part of the ships permanents magnetism, and consequently must be corrected by perm

18、anent magnet correctors. It is the principal cause of deviation changes on a magnetic compass. Subsequent reference to permanent magnetism will refer to the apparent permanent magnetism which includes the existing permanent and sub-permanent magnetism. 一艘船舶各种结构所具有的磁性，它会随着航行，振动，老化而趋于改变，但却不是立刻改变，以致这种磁

19、性很恰当地被当作感应磁性，被称为半永久磁性。在任何时候这种磁性都是船舶永久磁性的一部分，所以必须利用永久磁铁修正器来修正。它是在罗经中引起罗经自差改变的最重要的因素。后来证明了对于永久磁性来讲，船舶现有的半永久磁性将影响船舶表面上的永久磁性。 A ship, then, has a combination of permanent, sub-permanent, and induced magnetism. Therefore, the ships apparent permanent magnetic condition is subject to change from deperming

20、, excessive shocks, welding, and vibration. The ship induced magnetism will vary with the earths magnetic field strength and with the alignment of the ship in that field. 一艘船舶是永久半永久和感应磁性的组合体。然而，船舶表面永久磁性的情况是随着过分摇荡，焊接和振动而磁性改变减少。船舶感应磁性也会随着地球磁场强度以及船舶在地球磁场中所处位置的变化而变化的。 IV Induced Magnetism and Its Effect

21、s on the Compass感应磁性及其在罗经上的影响Induced magnetism varies with the strength of the surrounding field, the mass of metal, and the alignment of the metal in the field. Since the intensity of the earths magnetic field varies over the earths surface, the induced magnetism in a ship will vary with latitude,

22、heading, and heel of the ship. 感应磁性随着周围磁场的强度，金属的数量，金属在磁场中的定位的变化而变化。由于地球磁场强度在地球表面各不相同，船舶的感应磁场会随着纬度，船首向，船舶的纵横倾的变化而变化。 With the ship on an even keel, the resultant vertical induced magnetism, if not directed through the compass itself, will create deviations which plot as a semicircular deviation curve

23、. This is true because the vertical induction changes magnitude and polarity only with magnetic latitude and heel, and not with heading of the ship, Therefore, as long as the ship is in the same magnetic latitude its vertical induced pole swinging about the compass will produce the same effect on th

24、e compass as a permanent pole swinging about the compass. 当船舶处于平吃水状态，合成垂直感应磁性如果没有通过罗经自身的处理，将会增加自差，该自差被绘画出来是一条半圆形的自差曲线。这是真实的，因为垂直感应强度改变磁强度和极性，只与地磁纬度船舶倾侧有关，而与船首向的改变无关。因此，只要船舶在相同的地磁纬度，它的垂直感应磁极围绕罗经的摆动将在作为永久磁铁围绕罗经摆动在罗经上产生相同的影响。 The earths field induction in certain other unsymmetrical arrangements of hor

25、izontal soft iron creates a constant A deviation curve. In addition to this magnetic A error, there are constant A deviations resulting from: ( 1 ) physical misalignments of the compass, pelorus, or gyro; (2) errors in calculating the sun a azimuth, observing time, or taking bearings. 在地球磁场中，水平软铁产生出

26、不对称分布的恒定的自差曲线。这种恒定误差的存在是由于:（1）罗经，哑罗经，陀螺罗经的物理定位误差；（2）计算太阳方位角，观测时间，或获取方位的误差。 The nature, magnitude, and polarity of all these induced effects are dependent upon the disposition of metal, the symmetry, or asymmetry of the ship, the location of the binnacle, the strength of the earths magnetic field, an

27、d the angle of dip. 自然磁性和极性所有这些感应都取决于金属的倾向、船舶的对称性、罗盘箱的位置、地磁场的强度和俯视的角度。Certain heeling errors, in addition to those resulting from permanent magnetism, are created by the presence of both horizontal and vertical soft iron which experience changing induction as the ship rolls in the earth s magnetic f

28、ield. This part of the heeling error will naturally change in magnitude with changes of magnetic latitude of the ship. Oscillation effects accompanying roll are maximum north and south headings, just as with the permanent magnetic heeling errors.倾斜角的误差除了由于船舶在地磁场的转动的水平或垂直的软铁引起的永久性的磁性外，这部分的倾斜误差也随着船舶在地

29、球纬度的变化而自然地改变，当船首向为南北向时，波动影响转动达到最大化，这也将引起固定磁体倾斜角误差。V Detailed Procedures for Compass Adjustment磁罗经校正的详细程序The Adjustment Check-off List gives the physical checks required before beginning adjustment. The adjustment procedure assumes that these cheeks have been completed. The navigator will avoid much

30、delay by making these cheeks before starting the magnet and soft iron corrector adjustments. The most important of these checks are discussed below.在校正之前需要给出一份校正列表，这些校正程序假设已经完成了，驾驶员在开始磁铁和软铁校正之前应尽量避免制作这些核对的拖延。这最重要的核对拖延如下：Should the compass have a small bubble, add compass fluid through the filling pl

31、ug on the compass bowl. If an appreciable amount of compass liquid has leaked out, check the sealing gasket and filling plug for leaks.如果磁罗经中有水泡，需通过磁罗经盘上的塞子处填充液体，如果明显出现磁罗经液体的泄露，检查密封垫和填充塞子，以防泄露。Take the compass to a place free from all magnetic influences except the earths magnetic field for tests of

32、 moment and sensibility. These tests involve measurements of the time of vibration and the ability of the compass card to return to a consistent reading after deflection. These tests will indicate the condition of the pivot, jewel, and magnetic strength of the compass needles.把磁罗经放到除了地磁场远离其他磁场的地方，目的

33、是测试瞬时敏感性，这试验涉及震动时间的测量和罗经导致读数一致偏差的能力，这试验也指出中心转轴、宝石轴承和罗针的磁力强度的情况。Next, check the spheres and Flinders bar for residual magnetism. Move the spheres as close to the compass as possible and slowly rotate each sphere separately. Any appreciable deflection (2or more) of the compass needles resulting from t

34、his rotation indicates residual magnetism in the spheres. The Flinders bar magnetization check is preferably made with the ship on an east or west compass heading. To make this cheek: (a) note the compass reading with the Flinders bar in the holder; (b) invert the Flinders bar in the holder and agai

35、n note the compass reading. Any appreciable difference (2or more) between these observed readings indicates residual magnetism in the Flinders bar. Spheres or Hinders bars which show signs of such residual magnetism should be annealed, i. e., heated tea dull red and allowed to cool slowly.接下来，为了其他领域

36、剩余磁感应检查，夫林德棒，移动剩余范围使磁罗经尽可能靠近，慢慢的旋转使之分离出来，许多由于旋转而使罗针产生明显的偏角（2度或更多）估计在这个范围内的剩余磁感力。当船舶罗经首向为东西方向时，夫林德棒磁化，核对时更可取的。为了核对：（a）在支持器上的夫林德棒注释罗经读数（b）把夫林德棒反转过来再读一次罗经读数，在这些读书中的不同读数，(2度或更多)估计夫林德棒上的剩余磁感力，感应剩余磁感应强度的其他领域和夫林德棒应被退化，热度边暗红，慢慢的变红，慢慢的冷却。Correct alignment of the lubbers line of the compass, gyro repeater, an

37、d pelorus with the fore-and-aft line of the ship is important. Any misalignment will produce a constant error in the deviation curve. All of these instruments may be aligned correctly with the fore-and-aft line of the ship by using the azimuth circle and a metal tape measure. Should the instatement

38、be located on the centerline the ship, a sight is taken on a mast or other object on the centerline. If the instrument is not on the centerline, measure the distance from the centerline of the ship to the center of the instrument. Mark this distance off from the centerline forward or abaft the compa

39、ss and place reference marks on the deck. Take sights on these marks.修正磁罗经排列成行的长线，分罗经和船舶首尾哑罗经的线是非常重要的。在自差曲线中角度偏差将产生固定的错误，通过利用方位测定器和金属测深量度，所有的这些工具都可以正确的校准船舶的首尾线，这仪器位于船舶中心线处，一个看得到的中心线。为了标准上或者其他物体上，如果这仪器没有在中心线上，可确认船舶上的这条中心线与仪器之间的距离。标记从中心线或船尾的距离，查询在甲板上对应的标志并标记。Align the compass so that the compass lubbe

40、rs line is parallel to the fore-and-aft line of the ship. Steering compasses may occasionally be deliberately misaligned in order to correct for any magnetic error.对准磁罗经，使之对应的长线与船舶首尾线平行。为了修改磁罗经的错误，可以使磁罗经故意不对中。Adjust the Flinders bar first because it is subject to induction from several of the correc

41、tors and its adjustment is not dependent on any single observation. To adjust the Flinders bar, use one of the following methods:校正夫林德棒首先是因为她可以引起不同的误差，它的调节不仅依靠单一的因素。校正夫林德棒用以下方法之一：Use deviation data obtained at two different magnetic latitudes to calculate the proper length of Flinders bar for any pa

42、rticular compass location.用自差数据得到两种不同的磁纬度，选取许多特殊磁罗经的位置计算夫林德棒的本身长度。If the above method is impractical, set the Flinders bar length by a. Using a Flinders bar length determined by other ships of similar structure; and b. Studying the arrangement of masts, stacks, and other vertical structures and esti

43、mating the Flinders bar length required如果上述方法行不通，用一个夫林德棒通过其他船相似的构造来确定夫林德棒的长度。通过研究排列的桅杆，烟囱排气管或其它垂直结构来估算夫林德棒的长度。If these methods are not suitable, omit the Flinders bar until the required data are acquired.如果这些方法都不适合，忽略夫林德棒直到获得需要的数据。The iron sections of Flinders bar should be continuous and placed at

44、the top of the tube with the longest section at the top. Wooden spacers are used at the bottoms of the tube. 夫林德棒的铁部件可以继续代替顶部最长的部件管，隔板被用于管的顶部。Having adjusted, the length of Flinders bar, places the spheres on the bracket arms at an approximate position. If the compass has been adjusted previously, p

45、lace the spheres at the position indicated by the previous deviation table. In the event the compass has never been adjusted, place the Spheres at the midpoint on the bracket arms.如果已经校正了夫林德棒的长度，在概位上的托被臂，夫林德棒可以代替如果以前已经校正过，用之前自差的数据可以指出代替这一领域。如果在这一项磁罗经从来没有校正过，用托被臂的中点处代替这一区域。The next adjustment is the

46、positioning of the heeling magnet using a properly balanced dip needle.接下来使用校正平衡的磁倾仪来校正倾斜角磁铁的位置。These three dockside adjustments (Flinders bar, quadrantal spheres, and heeling magnet) will properly establish the conditions of mutual induction and shielding of the compass. This minimizes the steps re

47、quired at sea to complete the adjustment.这三个港区校正（夫林德棒，四分之一圆周区域，倾斜角磁铁）将证实与磁罗经互相作用和屏蔽的作用，这将切实减少在海上完成校正。Before proceeding with the adjustment at sea the fallowing precautions, should be observed: secure all effective magnetic gear in the normal seagoing position; make sure the degaussing coils are secu

48、red, using the reversal sequence, if necessary.在海上校正这些程序之前应注意下列预防措施：在一般适合远航当中应获得有效的磁力离合器，如有必要用反向轮换确保获得消磁圈。The adjustments are made with the ship on an even keel, swinging from heading to heading slowly, and after steadying on each heading for at least 2 minutes to avoid Gaussian error. 这种校正是通过船舶在平吃水

49、状态下缓慢地从船头转向船头并在船首位置至少停留两分钟避免高斯误差来实现的。Most adjustments can be made by trial and error, or by routine procedure. However, the procedures presented below provide analytical methods in which the adjuster is always aware of the errors magnitude on all headings as a result of his movement of the different correctors. 许多校正可以通过试验和常规的程序获得然而这程序呈现以下供给的分析方法，这种方法调整者通过知道船首的移动可以得到不同的误差结果。An