Qingdao Luhang Marine Airbag and Fender Co.,Ltd

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Briefly Tell You How to Select Marine Airbags for a Marine Project
- May 28, 2018 -

Marine airbags are found to be powerful and versatile tools for many marine projects such as disembarking ships, heavy transportation, re-floating salvage etc. But how to select suitable marine airbags for a specific project? As a professional manufacturer of marine airbags, I hereby give you a briefly introduction.

Marine airbags are widely used for ship launching, heavy transportation and marine salvage nowadays. Marine airbags are often called ship launching airbags that indicate the most popular application of these heavy duty airbags is for ship launching. It is estimated that more than 80 percent new built ships who’s DWT below 60,000 are launched by marine airbags.

Marine airbags are found to be powerful and versatile tools for many other marine projects such as disembarking ships, heavy transportation, re-floating salvage etc. But how to select suitable marine airbags for a specific project?

Marine airbag's specifications

Select the airbag's effective length not less than the maximum width of vessel or anything you want to move by airbags. But when you arrange two rows of airbags keep in mind to calculate the total length to avoid contact of airbags in two rows. The total length of airbags can be estimated to be effective length plus diameter. Let us say an airbag whose effective length is 16 meters and diameter is 1.5 m then its total length is 17.5 m.

Diameter of airbag is decided by the height of your vessel's support blocks. If the support block is 1 m high, then you should choose airbag's diameter not less than 1.5 m. If you get 1.5 m high blocks, the airbag with 2m diameters will suits you well.

For air lift use, airbag's diameter or length is mainly decided by the buoyancy you need from airbag. And also consider the pressure of airbag stands if you apply airbags in deep water.

For caisson transport by marine airbags, the most suitable diameter is 0.8-1 m. Marine airbag's performance is decided by its component plies. For air lift use or light vessel (launch weight below 2000 tons) launch, mid-pressure airbags are enough. For heavy duty work, the high pressure airbag should be selected. Generally speaking, airbags with 6-8 plies are enough for most engineering works. Only in some rigorous situation, airbags will need 9-10 plies to enhance its performance. For example, if people use airbags to lift heavy caisson but their contact area is limited, and then airbags will need higher pressure and more plies to ensure the safety. 

Reference for marine airbag selection  

There are two industrial standards for marine airbags in China.: one is product standard named "Air bag for ship up to or down to launching way "(CB/T 3795-1996 / CB/T 3795-2009); another is technology standard named "Technological Requirements for ship Upgrading or Launching Relying on Air-bags"(CB/T 3837-1998).The latter offer the basic calculation of marine airbags employed in a marine project.

According to Chinese industrial standards people will know the approximate quantity and specifications of marine airbags needed for their projects then consult the manufacturer to confirm the design. There maybe optional specifications to be selected for a specific marine project and a good manufacturer should know the best choice. The data of marine airbags' blasting pressure will reveal the product's quality level. For top quality marine airbags, such as one 1.5 m diameter and 7 m length Luhang marine airbag, the blasting pressure is 0.67 Mpa which indicates the safe coefficient is more than 5 considering its 0.12Mpa working pressure.

Full technical service is the qualification of a good company. Although general calculation formula or performance data of marine airbags can be got from most factories but detailed calculations based on mathematic model and experience is more important to the success of marine projects.

In a word

Good selection of marine airbags is vital for the success of marine projects. Get basic knowledge of marine airbags selection then consult with manufacturers can help people complete projects in shortest time.