Mono Buoyancy Unit (SPB)

Single Point Buoyancy Units

Professional Pipeline Laying Floats and Buoys

Single-point buoyancy units are one-kind enclosed pipeline buoyancy bags. They only have one single lifting point, so they are very effective for steel or HDPE pipeline laying work at or near the surface. Moreover, they can also work at a large angle, like parachute-type air lift bags. 

Vertical single-point buoyancy units are made of heavy-duty PVC coating fabric material that complies with IMCA D-016. Each enclosed mono buoyancy bag is fitted with pressure relief valves, and filling/discharge ball valves. One internal strop is used to connect the top lifting point with the bottom lifting point. We also can make lifting belts from the top to the bottom to reinforce the lifting capacity.

DOOWIN makes mono buoyancy bags with a capacity of less than 5ton. For the bigger capacity, you can choose our parachute air lift bags.

Meet IMCA D016

We design and test the single-point buoyancy units according to IMCA D016. The safety factory is over 5:1.

Auto Pressure Relief Valves

Single point buoyancy units are equipped with pressure relief valves. It can open automatically. 

Various Design

We can make various pillow-shape lift bags to meet different applications. 

Heavy Duty Material

Made from SGS certificated heavy-duty fabric, Superior abrasion resistance, UV-resistant, HF welded.

Two Filling Ports Design

There are two 3/4” stainless steel ball valves on the top of MBU. Can fill several airbags at the same time.

Single Lifting Point

Mono buoyancy bags have only one single lifting point for big-angle work. They are easy to connect and release.

Single Point Buoyancy Units Specification

DOOWIN single point mono buoyancy bags have 500kg, 1t, 2t, 3t, 5t common size. The standard color is yellow. The orange color is available upon request. Refer to the below pictures, we also can design and supply upon clients’ request, and special projects.

Model

Capacity

Diameter

Length

Dry Weight

SPB-500

500 kg

800 mm

1,100 mm

15 kg

SPB-1

1,000 kg

1,000 mm

1,600 mm

20 kg

SPB-2

2,000 kg

1,300 mm

1,650 mm

30 kg

SPB-3

3,000 kg

1,500 mm

2,300 mm

35 kg

SPB-5

5,000 kg

1,700 mm

2,650 mm

45 kg

Note: The specification is only for your reference. We may change its size without notice. 

Quality Assurance

DOOWIN single point buoyancy units are type certified by the drop test. It has proven a safety factor over 5:1. Our single point buoyancy units are manufactured and tested in compliance with IMCA D016. We can provide BV, ABS, LR third party certificate upon request.

Drop Loading Test

We did the drop test for all sizes single point buoyancy units. 

Hydraulic Blasting Test

We did the hydaulic blast test to test its maximum working pressure.

Third Party Certificate

We can provide test certificates from third-party testing agencies such as CCS, BV, SGS, ABS, apave, etc. 

Deepwater Buoyancy Test

Allseas conducted a deep water buoyancy test on our SPB-5 at a depth of 23 meters.

Practical Applications of Single Point Buoyancy Units

Feb 2025 — The Saudi Arabian Jizan Industrial City Seawater Cooling Project, undertaken by China Harbour Engineering Company and participated in by CCCC Fourth Harbor Engineering Bureau Co., Ltd., has completed the shipment and installation of high-density polyethylene (HDPE) pipelines in unprotected waters. The total length of the HDPE pipeline installed in the project is about 6,600 meters, and the pipeline diameter reaches 3.5 meters. It is currently the largest submarine HDPE pipeline installed in the world. 

June 2016 – The Saudi Arabian Jizan JIGCC drainage project has successfully installed a 3-meter diameter submarine HDPE pipeline. The flexible HDPE submarine pipeline with a length of 558.2 meters and a weight of1,315 tons was commercialized at the commercial port of the Saudi Arabian Sea City. It successfully adopted double-tube shipping to achieve seamless underwater docking and became the world’s first super-flexible HDPE submarine pipeline. Double pipe shipment installation. The Second Engineering Company of CCCC Fourth Harbor Engineering Co., Ltd finished this project.

Our customers are all over the world

DOOWIN is committed to providing high quality proof-load testing water weight bags and air lifting bags for our customers worldwide. 

Inflatable Buoyancy Units

We offer specially designed sausage-type water-filled proof load bags to do the Static and dynamic testing for the lifeboats and davits 

Twin Booom Buoyancy Units

Our load-measuring products include portable tension load links and load-measuring shackles both in wireless monitor.

Elongated Pipeline Buoyancy Units

We offer specially designed elongated sausage type water-filled proof load bags to test gangways.

Inflatable Cable/Pipeline Floats

Pillow-type water tanks can be used to verify the structural integrity of buildings, bridges, elevators, loading ramps, gangways, accommodation, ladders, and decks.

Marine Salvage & Buoyancy Assistance

DOOWIN specializes in manufacturing high-performance underwater air buoyancy bags designed for marine salvage, buoyancy assistance, and emergency rescue operations. Crafted from durable, high-strength materials, our bags are engineered to withstand extreme underwater pressures and harsh environments. Available in multiple sizes and load capacities, they offer versatile solutions for lifting sunken objects, stabilizing submerged structures, or providing critical flotation support during rescue missions.

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