How To Select Marine Airbags?

Introduction

Marine airbags have shown they work well for a wide range of marine tasks in various offshore projects. These include ship launching, marine salvage, and heavy transport. According to statistics, around 80% of ships with less than 60,000 dwt rely on marine airbags for activation during the critical process of launching a new vessel. This raises a thought-provoking question. When faced with a variety of offshore projects, do we know how to select the marine airbags for a particular project?

For shipyards venturing into airbag applications for the first time, selecting marine airbags can be a vexing task. However, the selection of marine launching airbags is not complicated. It only requires consideration of some key aspects. As a professional airbag manufacturer and engineer, Jerryborg Marine understands the importance of choosing the right airbags for marine projects. Our company wants to share suggestions to help you make an informed and precise airbag selection for your project.

Table of Contents

How to choose the airbag diameter?

When choosing the diameter of a marine airbag, consider the project requirements, the height of the supported object, and the specific conditions of the marine project. Here are some suggestions to help you make an informed choice among the many diameter options.

Applicable airbag diameter range:Jerryborg Marine offers airbags in a variety of common diameters including 0.8m, 1.0m, 1.2m, 1.5m, 1.8m, 2.0m and more. Choosing the right diameter will both ensure a safe launch/landing and help save costs. Remember two principles here: the airbag’s diameter should be greater than the keel block’s height under the boat. Also, choose the smallest diameter that meets the project’s needs.

Consider the height of the supporting object: The diameter of the marine airbag is closely related to the height of the block beam supporting the object to be moved. For example, if the height of the supporting block is 1m, an airbag with a diameter of not less than 1.5m can be selected. If the height of the block is within the range of 1.2~1.5m, airbags with a diameter of 1.8m or 2m can be considered.

Buoyancy and deep water applications: For marine salvage airbags, buoyancy is a crucial consideration. It determines the diameter and length of the rubber body. When used in deep water, attention needs to be paid to the airbag’s pressure. This ensures it can withstand the higher water pressure and keep you safe.

Diameter and number of layers of the lifting airbag: For heavy-duty lift airbags, the diameter is closely related to the number of plies comprising it. Medium-pressure airbags are suitable for relatively light objects. High-pressure airbags are designed for heavy-duty operations. The number of piles you choose depends on specific lifting needs. For example, when lifting heavy structures with limited contact surfaces, a higher pressure and number of piles airbag may be a safer choice.

When selecting airbag diameters, refer to standard codes such as CB/T 3795 – 2009 and CB/T 3837 – 1998. They provide more information on marine engineering quantities and specifications. For design advice for a specific structure, please feel free to contact Jerryborg Marine’s team of specialized engineers. We will advise you on the best solution for you.

How To Select Marine Airbags?

How do I choose an airbag length?

When choosing the length of a marine airbag, key considerations include the maximum width of the item. Also consider how the airbag is arranged and the specific characteristics of the vessel. Here are some suggestions to help you choose the right airbag length for various scenarios:

For airbags arranged in a single row: The airbag length should not be less than the maximum width of the item to be moved. Make sure the airbags will cover the item enough to give it the support and stability it needs.

For two rows of airbags: The overall length of the marine airbag can be estimated as the effective length plus the diameter of the marine airbag. For example, if the effective length of the airbags is 14m and the diameter is 1.3m, the total length will be 15.3 m. This configuration is suitable for specific projects. It is used when mutual support and stability of the airbags is considered.

Range of common airbag lengths: Common airbag lengths typically range from 5m to 25m. When selecting airbag lengths, consider how the airbags will be arranged. There are three main arrangements for end-firing airbags: linear, staggered, and two rows.

Relationship between ship width and airbag length: When the ship is not wider than 25m and we arrange the airbags in a line, the airbags should be longer than the ship’s width to cover the hull.

When the ship’s width is greater than 25m and a staggered arrangement is chosen, divide the ship’s width by 2. Add 1-2 meters to determine the length of the airbags to ensure coverage of the entire ship’s width.

When the ship’s width is greater than the sum of the effective lengths of the two airbags (25m/each airbag), or for special ships such as catamaran HSC or split-bottom barge, a two-line arrangement should be chosen. This ensures reasonable distribution and stability of the airbags.

When choosing the length of airbags, consider the specific needs of the project and the ship’s characteristics. Adjust the length flexibly to achieve the best support effect. You can do this by taking into account the different arrangements and ship widths. For more detailed design suggestions, please feel free to contact our team of professional engineers.

Conclusion

When selecting a marine airbag, key considerations include project requirements, the size of the supporting object, marine engineering conditions, and the arrangement of the airbag. Choose an appropriate diameter to ensure stability and safety. The airbag length needs to cover the maximum project width. Consider single or double row arrangement. Referring to standard specifications and relying on professional engineers’ advice can ensure the best performance of airbags in offshore projects. Taking all factors into consideration can also improve project efficiency.

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