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1、Unit 12 Anchoring and Berthing Operations 锚泊操纵I BERTHING IN WIND 风中锚泊1. The center of lateral resistance 侧向阻力中心 The force of the wind causes the ship to drift and, by doing so, hydrodynamic forces act on the underwater hull to resist the effect of the wind. The point of influence of these underwater
2、 forces is known as the centre of lateral resistance(CLR) and is the point on the underwater hull at which the whole hydrodynamic force can be considered to act. Similarly, there is a point of influence of wind(W) which has an important relationship with the CLR. W is likely to alter frequently as i
3、t will change in relation to the wind direction and the ships heading.风的作用使船舶偏航,这样,水动力作用于水下船壳抵消风的效果，这些水下部分作用力的中心被称为侧阻力的中心(CLR),也可以理解为是在整个动力的力量对 船壳的作用中心。同样的,其中有一个风的作用点(W) 跟CLR有着重要的关系。,由于风风向和船舶航向的相对变化，风力作用中心常常是变化不定的。To anticipate the affect wind will have on a ships heading, W must be viewed in relati
4、on to CLR. 为了预测风力作用如何影响船舶航向,我们必须把风的作用看做作用在侧向阻力中心。Ship handlers prefer to refer to pivot point (P) rather than CLR when discussing the effects of wind on a ship with headway or sternway . However, a stopped ship does not have a pivot point and for this reason CLR should always be used. In the discuss
5、ion which follows, CLR is used for a stopped ship and P for a ship with motion.当讨论风力作用对船首向/船尾向的影响时，船舶操纵者更喜欢引用转心(P) 而非CLR。然而,静止的船舶是没有转心的 ,因为这个原因,CLR也经常被使用。在接下来的讨论中,CLR是用在 静止的船而转心是用在航行的船舶。2. The point of influence of wind 风力作用中心The point of influence of wind (W) is that point on the ships above-water
6、structure upon which the whole force of the wind can be considered an act. 风力作用中心(W)是可以被认为是作用在船舶上层建筑的风力作用的那一点。Unlike a ships centre of gravity, the point of influence of wind moves depending on the profile of the ship presented to the wind. When a ship s beam is facing to the wind, W will be fairly
7、close to the mid-length point, slightly aft in the case of ships with aft accommodation and slightly forward if the accommodation is forward.与船舶的重心不同,风力作用中心取决于船舶的受峰面积。当一艘船的正横受风，风力作用中心会接近船长中点处，假如居住区在船尾，风力作用中心会稍稍向后，而住宿在船首则稍向前。 A ship will always want to settle into a position where the point and point
8、 of influence of wind in are in alignment.一艘船舶总是希望位于一个阻力中心和风力作用中心在一条直线互相抵消的位置 Ship stopped-ship with accommodation block aft: On a stopped ship with the wind on her beam , W will be close to the ships mid-length. When stopped in the water, the CLR is also at its min-length. The difference in locatio
9、n between the two points produces a small couple, and the ship will turn with head towards the wind. As a ship turns , W moves until it is close to the CLR ,when the couple reduces to zero. The ship will settle on this heading, usually with the wind slightly forward of the beam. * 拥有船尾生活区的停泊船：停泊船的正横
10、来风，风力作用中心靠近船长中点处。当船舶停泊在水中,CLR也是靠近船长中点处。处于不同位置的两个作用点之间产生一个小力矩，并促使船首转向上风处。随着船舶的转向，风力作用中心将会移动直到当转向力矩为零，它将靠近阻力作用中心。通常在风会轻轻的吹响船舶正横作用下，这艘船将停泊在这个方向Ship with headway-ship with accommodation block aft: If a ship has headway , P is forward and the lever between W and P is large. The resultant force will cause
11、 the ships head to turn to the wind .*拥有船尾生活区的航行船：如果一个船舶全速前进，转心位距离船首较近则转心和风力中心的力矩很大 ，船首将转向上风向。*Ship with sternway-ship with accommodation block aft : If a ship has sternway , P is aft of W and the ships stern will seek the wind . However, and for the majority of ships , the complexity of the aft-end
12、 accommodation structure can cause W to move further aft as the ship turns. Eventually, the ship may settle with the wind broad on the quarter rather than the stern.*船尾生活区的倒车船：如果一艘船舶正在倒车，转心在风力中心的后面，则船尾找风。然而,对大多数的船只,由于船舶转向，船尾生活区结构的复杂性会导致风力作用中心继续向移动。最后,船舶将在四分之一船长受风，而非船尾受风的情况下稳定。3. Force of the wind 风力
13、作用Wind force can be estimated by the formula: 风力作用估算公式 F= vv W18000Where F is the wind force in tones per square metre, V is the wind speed in m/s(metres/second) and windage area is the ship exposed to the wind in square metres. Estimate windage area for a beam wind by multiplying length by freeboar
14、d and adding the profile area of the accommodation housing. For a head wind, multiply beam by freeboard and add the area of the bridge front. And, as any mariner will know, double the figure obtained for F and order one or more tugs with the nearest bollard pull. F是风压力,单位是吨每米平方, ,V是风速单位米/秒,w是受风面积,以平
15、方米为单位。当正横来风估算受风面积是船舶长度乘以干舷高度，并加上生活区侧面受风建筑。当船首来风时，是船舶正横宽度乘以干舷高度，再加上中部上层建筑层壁面积。每一名船员都知道,双倍的风压力会造成一个或多个拖轮的拉力来系固船舶。 This calculation gives an estimate of the total force of wind on a ships side. It will give an indication of the total power that tugs will need in order to overcome this force. 这个计算给出了船舶一
16、侧受风的总作用力的估算方法。它会获得一个需要拖船克服风力作用总功率的估算值。It should be remembered that a ship will always want to settle on a heading where the ships pivot point is in alignment with the position of the winds point of influence. When navigation on such a course, a ship will show good course-keeping properties. As a result, it is preferable to berth
