Introduction
When a ship sinks, a barge capsizes, or heavy equipment falls into the water, lifting it back to the surface is not easy. Divers, cranes, and special lifting tools are often involved. One of the most practical tools used in these situations is the marine salvage airbag.
Marine salvage airbags create buoyancy underwater. When they are inflated with compressed air, they provide lifting force that helps raise sunken objects from the seabed. Compared with large cranes or rigid pontoons, airbags are easier to transport, quicker to deploy, and usually more cost-effective.
Over the years, several types of salvage airbags have been developed for different lifting tasks. In this article, we’ll look at the most common marine salvage airbags and where they are typically used.
What Are Marine Salvage Airbags?
Marine salvage airbags are inflatable lifting devices used in underwater recovery operations. Their job is simple: create buoyancy so heavy objects can rise to the surface.
The working process usually looks like this:
- Divers place the airbags around or under the sunken object.
- The airbags are connected to an air supply.
- Compressed air is pumped inside.
- As the airbags expand, they generate buoyant force.
- The object slowly lifts off the seabed.
Most salvage airbags are built with strong rubber layers reinforced with synthetic tire cord fabric. This design helps them handle high pressure, rough surfaces, and heavy loads.
Depending on the lifting task, different airbag designs may be used.
Totally Enclosed Marine Salvage Airbags
Totally enclosed airbags are one of the most commonly used types in professional salvage work.
They have a fully sealed cylindrical structure, with air valves installed on the surface for inflation and pressure control. Because the air stays sealed inside, the buoyancy remains stable during the lifting process.
Typical uses
- Shipwreck lifting
- Floating docks or pontoons
- Raising submerged steel structures
Why they are popular
These airbags provide reliable lifting power and stable flotation, which makes them suitable for large and complex salvage operations.
Marine Rubber Salvage Airbags
Rubber salvage airbags are widely used in marine engineering projects. Their structure is similar to ship launching airbags, but they are designed specifically for underwater lifting.
They are made from multiple layers:
- Inner airtight rubber layer
- Reinforced cord fabric layers
- Outer protective rubber layer
Key advantages
- Strong resistance to abrasion
- High durability in seawater
- Ability to handle heavy loads
Typical applications
- Salvaging sunken vessels
- Lifting large pipelines
- Supporting underwater construction work
Because of their strength and durability, rubber salvage airbags are often chosen for heavy-duty lifting tasks.
Pillow Flotation Lift Bags
Pillow lift bags are flat and rectangular, which is where the name comes from. They are usually made from PVC-coated fabric instead of thick rubber.
These airbags are lighter and easier to handle, which makes them useful in smaller operations.
Common uses
- Recovering small boats
- Lifting underwater tools
- Light salvage tasks in shallow water
Most pillow lift bags provide relatively small buoyancy, often from a few hundred kilograms to several tons.
Steel Salvage Pontoons
Although not technically airbags, steel pontoons are often used together with inflatable lifting systems in large salvage projects.
These are rigid floating tanks made from steel. Once attached to a wreck and filled with air, they provide large amounts of buoyancy.
Advantages
- Very high lifting capacity
- Long service life
Limitations
- Heavy and difficult to transport
- Higher installation cost
Because of these factors, steel pontoons are usually used in large-scale ship salvage operations.
Parachute Type Underwater Lift Bags
Parachute lift bags have an open bottom and a shape similar to an inverted parachute.
Air enters from the top, while excess water escapes from the bottom. This design makes them easy to control underwater.
Where they are used
- Deep water lifting
- Commercial diving operations
- Recovering equipment from the seabed
These lift bags are simple and flexible, which makes them popular among diving teams and underwater recovery crews.
Choosing the Right Marine Salvage Airbag
Selecting the correct salvage airbag depends on several factors.
Lifting capacity
The airbag must provide enough buoyancy to lift the weight of the object.
Water depth
Deeper water creates more pressure, which affects airbag performance.
Shape of the object
Irregular shapes may require several airbags placed at different points.
Safety margin
Engineers usually add extra lifting capacity to ensure a safe operation.
Planning these details carefully helps prevent accidents and improves the efficiency of the salvage work.
Conclusion
Marine salvage operations often take place in difficult conditions, where traditional lifting equipment cannot easily be used. That’s why marine salvage airbags have become an important solution for underwater recovery.
Several types are commonly used, including:
- Totally enclosed salvage airbags
- Rubber salvage airbags
- Pillow lift bags
- Steel salvage pontoons
- Parachute lift bags
Each design serves a different purpose. By choosing the right type and size, salvage teams can lift heavy objects more safely and efficiently.
FAQ
What are marine salvage airbags used for?
Marine salvage airbags are used to lift sunken ships, equipment, or structures from the seabed. They create buoyancy when filled with air, allowing heavy objects to float upward.
How much weight can a salvage airbag lift?
The lifting capacity varies widely. Small lift bags may handle a few hundred kilograms, while large rubber salvage airbags can provide tens or even hundreds of tons of buoyancy.
Are salvage airbags reusable?
Yes. High-quality rubber salvage airbags are designed for repeated use. With proper inspection and maintenance, they can be used in many salvage operations.
Are salvage airbags safe?
When used correctly and within their rated capacity, salvage airbags are considered safe and reliable. Proper planning, correct placement, and pressure control are essential.
What is the difference between lift bags and salvage airbags?
Lift bags are usually smaller and used by divers for lighter tasks. Salvage airbags are typically larger and stronger, designed for heavy marine engineering and ship recovery projects.