Pillow Type Underwater Lift Bags are enclosed buoyancy lifting devices specifically designed for stable underwater lifting operations. Their flat, pillow-shaped structure allows the bag to sit firmly on the seabed while generating strong and evenly distributed buoyancy during inflation. This structural design makes pillow lift bags particularly effective for lifting objects that are resting on the seabed or partially buried in sediment.
Hongruntong Marine Pillow Type Underwater Lift Bags are constructed from heavy-duty PVC coated polyester fabric combined with multi-layer reinforcement technology. The fabric is engineered to withstand harsh marine conditions including saltwater corrosion, mechanical abrasion, and UV exposure. The internal load-bearing webbing network distributes lifting forces evenly across the bag body, preventing localized stress and ensuring reliable structural stability during lifting operations.
During a port expansion project, a construction contractor accidentally dropped a large steel fabrication frame into the water while transferring equipment from a barge to the dock. The steel structure weighed approximately 9 tons and sank to the harbor seabed at a depth of about 8 meters.
Due to the limited maneuvering space in the harbor and the difficulty of deploying large cranes near the structure, the project engineers decided to use Hongruntong Marine Pillow Type Underwater Lift Bags for the recovery operation. Divers first inspected the submerged structure and identified several secure rigging points where lifting straps could be attached.
Two pillow lift bags with lifting capacities of 5 tons each were positioned beneath the steel frame. Their flat design allowed them to rest securely on the seabed while supporting the weight of the structure during inflation. Additional slings were installed to stabilize the load and ensure balanced lifting.
Compressed air was slowly introduced into the lift bags through surface-controlled air hoses. As the bags expanded, they generated sufficient buoyant force to gradually lift the steel frame off the seabed. The divers carefully monitored the lifting process and adjusted the air supply to maintain stability.
Within approximately 40 minutes, the structure was lifted high enough to be secured with a dockside crane and safely transferred back onto the construction platform. The recovery operation was completed without damage to the structure or interruption to the construction schedule.
The contractor reported that the Hongruntong pillow lift bags provided excellent stability and lifting control. Their compact design and easy handling significantly simplified the recovery operation compared with conventional lifting equipment.
| Product Name | Underwater Lift Bags |
| Raw Material | TOP Grade PVC Coating Fabric |
| Type | Pillow |
| Size | 500kg, 1000kg, 5000kg 10000kg, etc |
| Thickness | 0.4-1.2mm, or as request |
| Color | Yellow, Blue, Black, etc |
| Density | 0.33-0.9g/cm³ |
| Safety Factor | 7:1 |
| Accessories | Valve, Inflatable Tube, Repair Material |
| OEM | Welcome |
| Warranty | 3 Years |
| Tolerances | +/- 0.03 on densities +/- 0.2 mm on thickness +/- 0 to +3mm on width +/- 0 to +3mm on length |
| Model | Capacity [kg] | Capacity [lbs] | Length [mm] | Width [mm] |
|---|---|---|---|---|
| HM-ULB100 | 100 | 220 | 1,020 | 760 |
| HM-ULB250 | 250 | 550 | 1,320 | 820 |
| HM-ULB500 | 500 | 1,100 | 1,300 | 1,200 |
| HM-ULB1000 | 1,000 | 2,200 | 1,550 | 1,420 |
| HM-ULB2000 | 2,000 | 4,400 | 1,950 | 1,780 |
| HM-ULB3000 | 3,000 | 6,600 | 2,900 | 1,950 |
| HM-ULB5000 | 5,000 | 11,000 | 3,230 | 2,030 |