User:Henry Zhang668/Ship launching airbag

Ship launching airbag refers to the air bags that can be used for launching a vessel,this kind of air bags is made of synthetic-tyre-cord reinforcement layers and rubber layes, > it is also known as marine airbags, it was invented in 1980,on January 20, 1981 the Xiao Qinghe shipyard launched a tank barge with marine airbags,and it is known as the first use of marine airbags. >

From then on,more and more shipyard began to use air bags to launching small and medium-sized vessels,especially in China and Southeast Asia.

In recent years,high strength material is uesd in air bag production,then air bags have much more bearing capacity,big vessels launching also began to use air bags,in October,2011,one DWT 75000T vessel launching with air bags successfully,setted a world record of

ship launching utilizing air bags,the next year,"He Ming" ship,one vessel with DWT 73000T,total length 224.8m,breadth 34m,depth 18.5m,also launching utilizing air bags successfully on June 6,2012.

Air bag Structure


Air bag consist of three parts,
 * 1) air bag body,cylindrical part of the air bag after being fully inflated with compressed air
 * 2) air bag head,conical parts connecting the body and the mouths of the air bag
 * 3) air bag mouth,metal valves mounted on both ends of the air bag for charging air or one end mounted a lug for air bag pulling.

Size
Diameter of air bag (D) varies such as 0,8 m, 1,0 m, 1,2 m, 1,5 m, 1,8 m, etc.

Length of air bag (L) is to be specified by the user.

model
Accoding to the synthetic-tyre-cord reinforcement layers number of air bags, air bags can be divided into 3 layers air bags,4 layers air bags,5 layers air bags,

6 layers air bags...normally air bags layers less than 10

Air bag bearing capacity
maximum load carrying capacity of the air bag, while it suffers no permanent deformation or damage

D is the original diameter of the air bag

H is the height of the compressed air bag

W1 is the width air bag contacting with ship bottom

P1 is the internal pressure of the air bag

L is air bag effective length

Bearing capacity =P1 × W1 × L

Air bag materials
An air bag is to be constructed of synthetic-tyre-cord layers,sometimes outer rubber layer and inner rubber layer are added.All materials shall be vulcanized firmly.