Archive for the Air lift bags Category

30,000 Bags of Potential…

Posted in Air lift bags, Underwater air lift bags on October 29, 2013 by Seaflex

It may not look like much, but this 50kg parachute-style air lift bag represents a significant milestone for UK buoyancy and ballast specialist Unique Seaflex.
Air lift bag number 30,000 from Seaflex

Destined to be part of a spread of air lift bags supplied on hire to Bibby Offshore for their North Sea operations, this bag carries the serial number 30,000 – a landmark in the 26-year history of the Isle of Wight based manufacturer.

Air Bag Roots

It is also in fact a case of return to roots for Seaflex, as when established as something of a cottage industry back in 1987 in a partitioned-off corner of an old boatbuilding shed, bags of this size were the core business – and the largest bag produced offered only 500kg of uplift.

In 2013, the largest bag produced at Seaflex’s purpose-built Cowes facility comes in at 50t -1000 times the capacity of this modest-looking 50kg bag.

Global Success

Mark Board, the now-retired founder of Seaflex, commented “When I started out 26 years ago I could hardly imagine the global success story that Seaflex would become today – and supplying the 30,000th bag is tribute to the hard work and dedication of everyone who has worked in the business over this time.”

60,000th Air Lift Bag?

“Seaflex owes a debt of honour to their many thousands of customers past and present, who have taken them to this notable milestone.  With the business going through a period of significant worldwide growth, we expect Seaflex to be supplying their 60,000th bag into the market a whole lot sooner than the year 2039.” added Harry Ghandi, CEO of the Unique Maritime Group – longtime Middle Eastern representatives of Seaflex, and owners of the business since 2011.

New Partner for the Netherlands

Posted in Air lift bags, Load test weights, Underwater air lift bags, Water filled load test weights on August 8, 2013 by Seaflex

Seaflex is pleased to announce the appointment of Robin Jansen of P.C. Marine Agencies BV as our new stockholding ballast agent for the Netherlands market.

Robin Jansen with Ballast Stock

Robin is now stocking Seaflex WaterLoad bags along with load shackles, as well as Seaflex Lifeboat Testing kits, at his Groningen facility – ready for immediate despatch to meet urgent customer requirements.  Robin will also be representing Seaflex’s market-leading range of buoyancy bags and associated installation aids within his home market.

You can visit Robin and Seaflex  on Stand 11.011 at the upcoming Offshore Energy exhibition at the Amsterdam RAI on October 15th & 16th.

Laying Underwater Pipelines and Cables

Posted in Air lift bags, inflatable buoyancy units on March 4, 2013 by Seaflex

Laying underwater pipelines and cables is fraught with difficulty and would be almost impossible without the use of buoyancy bags. Buoyancy aids make the process of moving and laying underwater objects a much simpler process through the use of a relatively simple technology based on a simple concept.


IBUs used for pipeline buoyancy

The ‘Overpressure’ Principle

Inflatable buoyancy aids are made from flexible materials and become squashed under pressure but expand as pressure decreases. They work on the principle of overpressure. As the bag is lowered deeper into the water, it decreases in volume because the air inside gets compressed and occupies less volume.

On the other hand, as it is raised the air expands and the volume of the bag increases. Buoyancy is equal to the mass of the water displaced by the bag, which is proportional to the volume of the bag. It follows, therefore, that buoyancy decreases as a bag is lowered deeper into the water and increases as it rises up. Using an air hose attached to the bag, more air can be pumped into it whilst in a compressed state. Then as the bag is raised it expands in volume quickly and a huge amount of buoyancy is created. Even a small buoyancy aid can easily lift a weight equivalent to five family cars.

ALBs and ILBs

The two basic types of buoyancy units are ALBs (Air Lifting Bags) and ILBs (Inflatable Buoyancy Units). ALBs are used in operations such as cable floatation where an object needs lifting from the sea bed. They have just one point of attachment, which means that they will remain upright at all times and can be used at any depth. ILBs are used to increase, for example, pipeline buoyancy close to the surface or the buoyancy of any static object just under the water. They cannot be used at great depths and have multiple points of attachment.

Generally, ALBs are the only option when salvaging a vessel or lifting a cable or pipeline deep under water. If an object such as a pontoon or a section of pipeline that is waiting to be laid needs to be floated on the surface of the water, then ILBs are the correct choice. However, there are many complications when working underwater and the choice is not always so simple so it is well worth consulting the experts before starting any work.

Air Lift Bags for Marine Salvage

Posted in marine salvage, Underwater air lift bags on November 8, 2012 by Seaflex
Open bottom air lift bag

Open bottom air lift bag commonly used for marine salvage

Marine salvage involves recovering a ship and/or its cargo from the seabed following a shipwreck or other maritime accident. Obviously, ships and cargo are heavy objects which cannot be recovered without specialist equipment and knowledge.

Underwater air lifting bags are specifically designed for the recovery of underwater objects that need lifting to the surface. They can also be used as static buoyancy in underwater engineering as they only need a single attachment point and are stable and easy to handle underwater.

Air Lift Bags

Air lifting bags are available in various designs and capacities, so that salvage operators can choose the appropriate level of buoyancy required to lift objects in a controlled fashion. For recovering heavy objects, such as a ship, multiple bags will be necessary to provide a balanced and controlled lift. This is important as objects that are lifted too quickly can reach the surface out of control, posing a risk to the operators and the vessel being salvaged.

Closed or Open?

There are two basic types of lifting bag:

  • Closed air lifting bags typically include a safety valve that allows air to be released for a steady, controlled ascent.
  • Open bottomed air lift bags work differently as their open bottom allows expanding air to vent freely during an ascent to the surface as pressure decreases.

For this reason, and the ease of handling, open bottomed air lift bags are usually the preferred choice for marine salvage. Their strength, ease of use underwater and predictable behaviour make them the most effective and safest option for most marine lifting operations.

Jean Ricciardi

Salvage of the Jean Ricciardi

When the trawler Jean Riccardi suffered a power failure, flooded and sank near the port of Sete, on the French Mediterranean coast, twelve open bottom air lift bags, capable of lifting 20 tonnes each, were used to complete the salvage operation quickly and safely.

Dunkirk ‘little ship’ Recovery

Posted in inflatable buoyancy units, marine salvage, Underwater air lift bags on November 1, 2012 by Seaflex

Skylark XI was one of the fleet of ‘little ships’ that rescued Allied soldiers from the beaches of Dunkirk in 1940 in Operation Dynamo. But for the last two years – since the 70th anniversary of Operation Dynamo – she has been lying on the bed of the River Leven at Balloch in West Dunbartonshire.

With the help of the Royal Navy Clearance Divers the Skylark IX was successfully re-floated on the 18th of October.

Little Ship salvage using Seaflex underwater airlift bags

Skylark salvage – image from

Using inflatable buoyancy bags the Royal Navy divers from the Faslane base on the Clyde undertook a painstaking 12-hour operation to refloat her. They had to abandon their efforts after the first day but eventually the last of the water was pumped out and the successful operation was completed.

The Skylark was one of the smallest of the “little ships” which responded to the call from Winston Churchill in 1940 to rescue the Allied forces trapped on the beaches of Dunkirk. Although her capacity was 90 passengers, on each of the four return trips into Dunkirk she brought out 150 exhausted and wounded soldiers .

Seaflex donated six, 2 tonne Inflatable Buoyancy Units with airlines and manifolds to use in the operation.

STV News article and News video footage on the first day’s attempt.
The Scottish Herald article and images.

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Salvage of the Jean Ricciardi

Posted in Air lift bags, marine salvage, Underwater air lift bags on October 4, 2011 by Seaflex

Jean Ricciardi Salvage using air lift bags

Client: Insurance company
Contractor: Prodive Monaco
Location: Sete, France
Water depth:  18m

The Jean Ricciardi had suffered a total power loss in the middle of the night and this left her without lights and adrift, she continued to drift until she ran aground under the cliffs near the harbour entrance of Sete.  A merchant vessel who caught sight of the Jean Ricciardi contacted authorities and took 2 crew members aboard who had been in the Jean Ricciardi’s liferaft at the time of the grounding. A lifeboat was dispatched and freed the fishing vessel from the rocks and the Jean Ricciardi was taken under tow bound for Sete.  The vessel’s hull had been severely damaged during the grounding allowing significant water ingress to the vessel and she started to heel.   Without power to operate the pumps the fishing vessel flooded and then sank by the stern just 800 meters from the harbour entrance.


Due to the water depth and the close proximity to the harbour entrance the Local harbour authorities insisted that the wreck be remove as soon as possible. The vessel’s insurance company agreed and engaged a salvage company to remove the wreck however they failed in their attempts. PRODIVE were then approached to carry out the removal and contacted SEAFLEX to supply the necessary air lift bags.

Jean Ricciardi Salvage using air lift bags

PRODIVE required 240t of lift bags, 12 x 20t ALB (Air Lift Bags) for despatch as soon as possible. The bags were packed and despatched from stock the same day from SEAFLEX head quarters on the Isle of Wight and arrived on site two days later.  The salvage was completed by PRODIVE within a week of the call to SEAFLEX and the Jean Ricciardi has now been safely removed from the water to be broken up for scrap.

For more information or quotation contact: Graham Brading –


Unique Maritime Group acquires Seaflex Ltd.

Posted in Air lift bags, inflatable buoyancy units, marine salvage, Underwater air lift bags on June 2, 2011 by Seaflex

Unique Maritime Group

Unique Maritime Group a leading provider of specialized engineering solutions to the subsea and offshore oil and gas industries worldwide announced the acquisition of Seaflex Ltd today (24th April 2011).  Seaflex Ltd.  is a leading provider of marine buoyancy products and water filled test weights. Seaflex’s product range includes, subsea air lift bags, inflatable buoyancy units, WaterLoad test weights, cable and pipeline buoyancy, lifeboat testing ballast bags, yacht fenders and yacht racing buoys.  Seaflex is a BS EN ISO 9001:2008 company, independently certified by Lloyds Register Quality Assurance and its products comply with current IMCA and EC regulations.

Lifting aircraft airframe using air bags

The purchase of Seaflex Ltd., based in Isle of Wight, further strengthens Unique Maritime Group’s strategic goal  to expand its Manufacturing , Sales & Rental operations for specialized products worldwide. “The acquisition is also expected to result in greater efficiencies and significantly increase our market share” said Harry Gandhi CEO of Unique Maritime Group.

Seaflex will continue to operate under the same name & Graham Brading will take over as Managing Director. Mark Board continues to provide valuable support to him as a consultant for next two years.

“The acquisition of Seaflex was a calculated decision and was accomplished through an exclusive negotiation process under the guidance of Pinsent & Masons as legal advisors.” explained  Harry.