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Chapter Three Navigation Technology 5~6 hours
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Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Jan 17, 2016

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Page 1: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Chapter Three

Navigation Technology

5~6 hours

Page 2: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Review what we have learned last period

Aids to Navigation System

Beacon

Lights

Lighthouses

Buoys

A lighted buoy

A wreck buoy

Lateral system and cardinal system

航标

灯标灯塔浮筒

灯浮

沉船浮筒

侧标系统和界标系统

Page 3: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Passage Two Navigation Process

Vocabulary

voyage planning 航次计划track [] n. 航路,航迹 operational commitment 营运任务construct [] vt. 设计,规划,构想 fundamentally [] adv. 根本上地,基本上地 unauthorized [] adj. 未经授权的,未经批准的deviation [] n. 偏离航向,自差,偏差,背离

There is something fundamentally wrong with your idea.

Finding and solving the deviation and problem in the test.

Page 4: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

great circle 大圆great circle chart 大圆海图sailings [] n. 航海术,航行,起航 eliminate [] vt. 除去,排除,消除 inherent [] adj. 内在的,固有的 waypoint [`] n. 航路点 leg [] n. 一段航程 computer-generated 计算机生成的applicable [] adj. 适用的 pilot chart 航路资料图,引水图inventory [] n. 详细目录,清单 inertial navigator 惯性导航仪

A mark or place at which a vessel is to report to establish

its position.

These principles are applicable to all minority

nationality areas.

Page 5: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Night Order book 夜航命令簿vehicle [] n. 工具,手段,交通工具,车辆pertaining to 与……有关submarine [] n. 水下状况,潜水艇 adj. 水下的 evolution [] n. 发展,进展 circumstance [] n. 环境,条件 render [] vt. 使得,提供,使成为 vi. 给与补偿 n. 交纳 continuously [] adv. 连续不断地 Standing Orders 常规命令簿fathometer [] n. 回声测深仪 CPA closest point of approach 最接近点,最近会遇点

The Night Order book is the vehicle by which the

captain informs the officer of the deck of the

captain’s orders for operating the ship.

The captain sets the ship’s navigation policy in these orders, for example, required fix intervals, intervals for fathometer operations, minimum CPA’s, and other general navigation and collision avoidance

requirements

Page 6: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Text

Voyage planning determines the safest and most ef

ficient track for the ship to follow to ensure that the

vessel completes its operational commitments. Con

structing a planned track for a voyage is fundament

ally important for ship’s safety. Several ships’ groun

dings have occurred because of unauthorized devia

tions from an approved track.

Page 7: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Construct the track using a navigation

computer, a great circle (gnomonic) chart, or

the sailings. This passage will only discuss the

navigation computer and the great circle chart.

Use a navigation computer if one is available

because the computer eliminates the plotting

errors inherent in transferring the track from

gnomonic to a Mercator projection.

如果有可能,就要使用航用计算机。计算机可以消除航迹从心射投影向墨卡托投影转换中所

固有的标绘错误。

Page 8: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

When using a navigation computer, the navigator simply inputs the two endpoints of his planned voyage. The computer computes waypoints marking the great circle track between the two endpoints. The computer determines each track leg’s distance and, given a speed of advance, calculates the times the vessel can expect to pass each waypoint. Construct the track on the Mercator chart by plotting the computer-generated waypoints and the tracks between them.

计算机计算出两个端点之间标记大圆航迹的航路点。

Page 9: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Prior to getting the ship underway, inspect all

navigation equipment, charts, and publications.

The navigator should develop a checklist of

navigation equipment specific to his vessel and

check that all required equipments are onboard.

The navigator should have all applicable Sailing

Directions, pilot charts, and navigation charts

covering his planned route. He should also

have all charts and Sailing Directions covering

ports at which his vessel may call.

Page 10: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

He should have all the equipments and publica

tions required to support celestial navigation. Fi

nally, he must have all technical documentation

required to support the operation of his electron

ic navigation suite. Complete this chart, publicat

ion, and equipment inventory well before the un

derway date and obtain all missing items before

sailing.

Page 11: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Determine gyro compass error at least daily as part of the at-sea routine. Check the gyro compass reading against the inertial navigator if the vessel has an inertial navigator. Report any error greater than 1° to the navigator and commanding officer. Check the gyro repeaters and the magnetic compass against the gyro compass hourly and after each course change. When comparing the magnetic and gyro compasses, navigator should determine changes in variation and deviation. Report any repeater error greater than 1° to the commanding officer.

Page 12: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

The Night Order book, despite its name, can

contain orders for the entire 24-hour period after

which the Captain signs it. Such orders include

assigned operating areas, maximum speeds

allowed, and, regarding submarines, the maximum

depth at which the ship can operate. Each

department head should include in the Night Order

book the evolutions he wants to accomplish during

the night that would normally require the captain’s

permission.

这些命令包括设定好的航行区域,最大许可船速,对于潜水艇而言,包括潜水艇的最大操纵水深。

每个部门的领导都要在夜航命令簿中写明他想在夜间航行中取得的进展,

这些指令通常要得到船长的许可。

Page 13: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

The captain can add further orders and directions as required. When the captain signs the Night Order book, it becomes an official order to the Officer of the Deck. The Officer of the Deck must not follow the Night Orders blindly. Circumstances under which the captain signed the Orders may have changed, rendering some evolutions ordered impractical to complete. The Officer of the Deck, when exercising his judgment on completing ordered evolutions, must always inform the captain of any deviation from the Night Orders as soon as such a deviation occurs.

甲板部的驾驶员在根据自己的判断完成命令簿中给出的指令时,如果出现相背于夜航命令簿的背离,应立即报告船长。

Page 14: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

The Commanding Officer’s Night Orders are in

effect only for the 24 hours after they are written;

his Standing Orders are continuously in force. The

captain sets the ship’s navigation policy in these

orders. He sets required fix intervals, intervals for

fathometer operations, minimum CPA’s, and other

general navigation and collision avoidance

requirements. The Officer of the Deck must follow

the Commanding Officer’s Standing Orders at all

times. Report any deviation from these orders

immediately to the Commanding Officer.

Page 15: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Passage Three

Rhumb lines and Great Circles

Vocabulary

loxodrome [] n. 恒向线 derive from 源自,来源于intersect [] vt. 与 …… 相交,相交oblique [] adj. 倾斜的 curvature [] n. 弯曲,曲度,曲率 inconvenience [] n. 不便,困难 appealing [] n. 引起兴趣的,动人的 slope [] n. 倾斜,斜度,斜坡 loxodromic curve 恒向线,等角航线

a line crossing all meridians or longitude at the same angle, i.e. a straight line path derived from a

defined initial bearing.

The line AB intersects the line CD at E.

Page 16: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

spiral [] vi. 成螺旋状旋转 n. 螺旋状物 stereographic projection 极射平面投影equiangular spiral 等角螺旋circumference n. 圆周analogue [] n. 类似物,模拟 oblate spheroid 扁球体 ellipsoid [] n. 椭圆体squash [] vi. 压扁,压制 geodesic [] n. 最短程线(连接平面或球面上两点之间的最短的线)approximation [] n. 近似值 aviation [] n. 航空

The stereographic projection must be supplemented by other constructions.

Page 17: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Text

In navigation, a rhumb line (or loxodrome) is a line crossing all meridians or longitude at the same angle, i.e. a straight line path derived from a defined initial bearing. That is, upon taking an initial bearing, one proceeds along the line defined by it, and continues this line without changing one’s true (not magnetic) direction.Its use in navigation is directly linked to the style, or projection of certain navigational maps. A rhumb line will always be a straight line on a Mercator projection map.

也就是说一旦采用了初始方位,船舶将沿着既定的路线航行,一直沿着这条航线航

行不需要改变真方向(不是罗方向)。

Page 18: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

On a plane surface this would be the shortest distance between two points over short distances, where the curvature of the earth is not a major factor, and thus can be used for plotting a ship’s course. Over longer distances great circle routes provides the shortest routes. However the inconvenience of having to continuously change bearings while travelling a great circle route makes rhumb line navigation appealing in certain instances. On a Mercator projection map, a loxodrome is a straight line; beyond the right edge of the map it continues on the left with the same slope.

平面上,这是短距离条件下两点之间最短的距离,这时地球的曲度不会造成什么影响,因此可以用来标绘船舶的航向。

然而采用大圆航路时要不断地改变方位造成了很大的不便,这就使在很多情况下利用恒向线进行航行更理想。

Page 19: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Meridians of longitude and parallels of latitude

provide special cases of the rhumb line, where

their angles of intersection are respectively 0°

and 90°. Rhumb lines which cut meridians at

oblique angles are loxodromic curves which

spiral towards the poles. On a stereographic

projection map, a loxodrome is an equiangular

spiral whose center is the North (or South)

Pole.

经度方向的子午线以及纬度方向的平行线都构成了恒向线的特殊情况,它们与

恒向线的交角分别是 0° 和 90° 。

在极射平面投影上,恒向线是等角螺旋,中心就是北极(或南极)。

Page 20: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

A great circle of a sphere is a circle that runs

along the surface of that sphere so as to cut it

into two equal halves. The great circle therefore

has both the same circumference and the same

center as the sphere. It is the largest circle that

can be drawn on a given sphere.

Page 21: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Great circles serve as the analogue of “straight lines” in spherical geometry. The great circle is the path with the smallest cruvature, and hence, an arc of a great circle is the shortest path between two points on the surface. The distance between any two points on a sphere is therefore known as the great-circle distance. The great-circle route is the shortest path between two points across the surface of a sphere.

球面几何

大圆是曲度最小的路线,因此大圆弧线是球面上两点之间最短的距离。

Page 22: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Strictly speaking the Earth is not a perfect

shpere (it’s an oblate spheroid or ellipsoid - i.e

slightly squashed at the poles), which means

that the shortest distance between two points (a

geodesic) is not quite a great circle.

Nevertheless, the sphere model can be

considered a first approximation.

Page 23: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

When long distance aviation or nautical routes are drawn on a flat map (for instance, the Mercator projection), they often look curved. This is because they lie on great circles. A route that would look like a straight line on the map would actually be longer. An exception is the gnomonic projection, in which all straight lines represent great circles. On the Earth, the meridians are all great circles, and the equator is a great circle. Other lines of latitude are not great circles, because they are smaller than the equator; their centers are not at the center of the Earth -- they are small circles instead.

Page 24: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Great circle routes are used by ships and aircraft where currents and winds are not a significant factor. If one were to travel along a great circle, it would be difficult to steer manually as the heading would constantly be changing (except in the case of due north, south, or along the equator). Thus, Great Circle routes are often broken into a series of shorter rhumb lines which allow the use of constant headings between waypoints along the Great Circle.

如果沿着大圆航行,人工操舵是非常困难的,因为船首向要不停地改变(除非在地球上最

南部,最北部或沿着赤道航行)。

Page 25: Chapter Three Navigation Technology 5~6 hours. Review what we have learned last period Aids to Navigation System Beacon Lights Lighthouses Buoys A lighted.

Summary of this period.

Home work:

1. Review what we have learned today.

2. Recite the new words and expressions.

3. Finish some of the exercises.

4. Preview next part of the text.