大型船舶操纵性能特点概要

大型船舶操纵性能特点概要

由于超大型船舶的尺度和载重量极大而主机相对单位吨位所具有的马力反而变小，

从而使超

大型船舶与一般

1

–

2

万吨级船舶在操纵性能上具有了很多需要注意的不同特点。

一．

操纵性能下降

1

．

舵效差，

反应迟钝，

甚至

3

–

4

节船速时已无舵效；

2

．

追随性差，

故在改向或过弯曲航道时，

需予以充分估计，及时施舵；

3

．

航向稳 定性

（方向稳定性）差，

施舵后，一旦船首开始偏转则需注意及 时压舵驶上

新航向；

4

．

保向性 能差，在风浪中航行因

B/L.D

值较高，易产生偏航；

5

．

D/L

值较低 ，呈良好旋回性能；

6

．

启动，停车惯性大，呈显出变速操纵较为呆笨，停船性能较差；

7

．

转向惯性大，故需施大舵角，早施舵，早回舵，施大压舵角；

8

．

紧急停船性能下降（停车惯性大）

。

二．

浅水，狭水道中受限水域中产生的效应更为明显

1

．

阻力增大，船速下降；

2

．

船体下坐，产生纵倾；

3

．

旋回性变差；

4

．

振动加剧，产生异常振动；

5

．

舵力产生变化；

6

．

航向稳定性提高；

7

．

因纵倾与横摇，要求足够的富裕水深；

8

．

沿岸航行，易产生侧壁效应；

9

．

因风，流压差，要求足够的海底宽度；

10

．追越与对驶时，保持必要间距，以防船吸效应。

三．

港内操船特点

1

．

由于港口码头水域有限，超大型船舶的操纵港作拖轮是主力；

2

．

靠离码头，横向移动需要使用多艘拖轮；

3

．

所配拖轮位置应据不同作业状态而应有所不同；

4

．

回转中需注意本船船尾的反移量。

四．

操纵用锚上的受限

1

．

锚泊时，几乎都是抛单锚锚泊；

2

．

如抛锚 调头等操纵用锚时，

应倍加注意，

因锚机制动力不足，

船速必须小于

1/4

节，

否则有危险；

3

．

因船舶 动量特大，一般不可应用锚来制动，最忌违的是航行中下锚；

4

．

一般均 采用深水抛锚法，

用锚机倒至海底，

松出一定长度锚链后，

再用常规方法松

链。

超大型船舶的船型均肥胖而粗短，其方型系数多高于

0.8

，船越大

C

B< /p>

亦越大，即是压载时

C

B

也可达

0.75

以上，

其长度 比

L/B

为

6.0

–

6.7

，

比一般货船小，

而宽与吃水之比多大于

2.5

< br>，

比一般货船大，其舵面积比

A/Lpp * d

多低于

1/65

，但却具有良好的旋回性，从 而使得超大

型船舶的追随性和航向稳定性能较差，

而旋回性能较 好，

主机功率随船型的增大而增大，

但

并不与其吨位成比例，

其单位吨位马力值有较大降低，

且其全速 倒车速度也仅能达到全速前

进时的

30%

左右，一般均在

6

节以下。

Outline of Manoeuvre Characteristics of VLV

Owing

to

the

large

measures

and

great DWT

of VLV

and

relatively

smaller

main

engine

horse

power per ton, there are many characteristics different from those of the 10,000 ton to 20,000 ton

vessels.

1.

Ship

’

s Manoeuvrability Coming Down

1.1

Bad steering: slow reaction, no rudder effect, turn at the 3-4 kt speed.

1.2

Bad

yaw

quick

responsibility:

make

enough

estimate

and

make

rudder

in

time

when

altering course or passing the bend channels.

1.3

Poor course stability (directional stability): after

making rudder pay attention to

make

opposite rudder in time the ship head being to slant.

1.4

Bad course keeping ability: in the storm weather, easy to be off course, because of low

B/L *D value.

1.5

Good

steady

turning

ability:

although

there

is

a

big

turning

circle, D/L

value

is

small

good turning ability appearing.

1.6

Big starting and stopping inertia: changing speed appear duller, stopping ability is not so

good.

1.7

Big turn inertia: in order to make big rudder angle, make rudder early, make early return

rudder, make big opposite rudder angle.

1.8

Because of big stopping inertia crush stopping ability comes down.

2.

More evidence effects in Shallow and Narrow Channel

2.1

Resistance increase, speed coming down.

2.2

Trim happening because of ship body sinking.

2.3

Steady turning ability becoming not so good.

2.4

Vibration intensifying, abnormal vibration appearing.

2.5

Course stability being better.

2.6

Rudder force changing.

2.7

Require enough U.K.C, because of trim and heel.

2.8

Bank effect easy to happen in narrow channel sailing.

2.9

Require enough breadth of sea bottom for leeway.

2.10 Keep necessary distance from other ship while is going to overtake or head-on.

3.

In the Harbor Manoeuvre Characteristics

3.1

Tugs become main force to maneuver VLV because of limited harbor water area.

3.2

Need several tugs to go alongside or leave berth or move transversely.

3.3

Need different tug disposition according to different tasks.

3.4

In turning process pay attention to the kick of own ship stern.

4.

Restricted to use Anchor in Manoeuvring

4.1

Almost use single anchor at anchorage.

4.2

Pay special attention to using anchor in maneuver, ex. Turning with anchor, speed have

to be less than 1/4 KT, otherwise there are dangers because the brake of windlass has no

enough break power.

4.3

Usually

don

’

t

use

anchor

to

brake,

for

the

ship

’

s

very

big

momentum.

Anchoring

in

navigation is prohibited.

4.4

Usually use the deep water mooring, anchor is to send by windlass to the sea bottom,

after sending out certain length of chain use normal method to slack chain.

VLV type ship is fat, short and bulk; its block coefficient is almost more then 0.8. The bigger the

C

b

,

even

in

the

ballast

C

b

will

be

more

then

0.75.

It

’

s

radio

of

length

and

breadth

is

6.0

–

6.7,

smaller then general cargo ship, but ratio of breadth and draft is more then 2.5 bigger then general

cargo ship. It

’

s ratio of rudder area and side area A

R

/Lpp * d is almost smaller then 1/65, but it has

good turning ability. So the yaw quick responsibility and the course stability of VLV are not so

good

but

the

turning

ability

is

better.

With

the

increase

of

the

ship

’

s

tonnage

the

main

engine

power is raised, but its HP per tone has bigger descend.

大型船舶操纵特性

1

．

大型船舶惯性

11

停车惯性

超大型船质量大

,

其冲程冲时均长， 一般至余速

5

节时的冲程达

14L

，

（

3

海里）

4

节时为

18L

，

3

节的冲程均达

23L

以上，冲时可达接近半小时。

12

倒车惯性

据

IMO

暂行规定，全速倒车停船行程不应超过

15

倍船长。

13

影响惯性因素

?

排水量

?

主机倒车功率及换向时间

?

船速

?

船型

?

外界因素

?

推进器种类

14

各种制动方法及其运用

?

倒车制动法：

倒车制动，

是一种有效的制动方法。

尤其是在低速航行时更 为见

效。但由于会出现较大的偏航量和偏航角，故在受限水域使用时应谨慎。