Parachute Subsea Airlift Bags: An Essential Tool for Underwater Lifting Operations

Underwater operations, whether in offshore oil fields, shipwreck recovery, or marine construction, often require the safe lifting and transportation of heavy submerged objects. Among the most reliable and effective tools for such tasks are Parachute Subsea Airlift Bags. These specialized lifting bags are engineered to assist in underwater recovery, salvage, and support operations by harnessing the power of buoyancy.

What Are Parachute Subsea Airlift Bags?

Parachute subsea airlift bags, also known as open-bottom lifting bags or buoyancy bags, are heavy-duty inflatable devices designed for vertical lifting underwater. They are shaped like parachutes—hence the name—and are used to lift sunken objects from the seafloor by providing controlled buoyancy.

These bags are typically made from high-strength PVC or urethane-coated nylon, ensuring durability and resistance to abrasion, oil, saltwater, and harsh subsea environments. Their open-bottom, single-point lift design allows water to escape freely as the bag inflates, making the lift smooth and stable.

Key Features and Benefits

1. High-Lift Capacity
Parachute airlift bags are available in various sizes, with lift capacities ranging from a few hundred kilograms to several tons. This makes them suitable for everything from small recovery tasks to large industrial subsea operations.

2. Versatile Application
These bags are used across industries including offshore oil & gas, shipping, marine construction, environmental recovery, and defense. Common applications include lifting pipelines, anchors, submerged equipment, and even aircraft wreckage.

3. Safe and Controlled Lifting
With a single lifting point and controlled inflation via surface-supplied or scuba-diver-managed air, operators can achieve precise and stable lifting. Safety features like pressure relief valves prevent over-inflation and bag damage.

4. Easy Deployment and Recovery
Thanks to their lightweight and flexible construction, parachute subsea airlift bags can be quickly deployed by divers or ROVs (remotely operated vehicles). After use, they can be deflated, rolled, and stored compactly.

5. Reusable and Cost-Effective
These bags are reusable over many operations, offering a cost-effective solution for companies conducting multiple underwater lifting projects.

How Do They Work?

The basic working principle of parachute airlift bags is Archimedes' principle—buoyant force. When the bag is inflated with air underwater, it displaces the surrounding water and creates upward force. This buoyant force lifts the attached object toward the surface.

The air can be supplied via umbilical from the surface or using diving cylinders. As the bag fills with air, it begins to rise. Because it’s open at the bottom, water exits easily, ensuring that the lift is not only powerful but also controlled.

The single-point lifting eye or bridle is used to connect the bag securely to the load, and in many operations, multiple bags can be used in tandem for very heavy or irregular-shaped loads.

Common Use Cases

• Salvage operations: Recovering sunken vessels, equipment, or cargo

• Pipeline and cable installation: Floating heavy lines into position before sinking

• Marine construction: Assisting with the placement or movement of underwater structures

• Aircraft recovery: Lifting crashed aircraft or drones from the seafloor

• Environmental cleanup: Removing heavy debris or hazardous waste from underwater sites

Safety Considerations

Despite their efficiency, parachute subsea airlift bags must be used with caution:

• Proper load assessment is crucial. The total buoyancy required must exceed the weight of the object in water.

• Controlled inflation helps prevent sudden ascents, which can be dangerous to divers and damaging to equipment.

• Operator training is essential. Divers should be familiar with the specific lifting procedure, inflation process, and emergency controls.

• Regular inspection of bags for wear, punctures, or valve issues is a must before each operation.

Final Thoughts

Parachute subsea airlift bags are indispensable tools in the underwater lifting and salvage sector. Their adaptability, strength, and cost-efficiency make them a preferred choice for marine engineers, divers, and salvage crews worldwide. Whether used in shallow coastal waters or deep-sea environments, they play a critical role in ensuring safe and successful underwater operations.

If your organization is involved in underwater construction, recovery, or salvage, investing in high-quality parachute subsea airlift bags—and partnering with a reliable supplier—can make all the difference in performance and safety.