MatJack underwater lifting bags were introduced back in 2004. Underwater lift bags come in lots of shapes and configurations to meet all your floatation needs whether it is in shallow streams or ocean depths.
The open bottom cushions fill from the top and displace water out of the bottom until either the submerged vessel begins to float to the surface or the bag fills and the relief valves open. These are used the best in water deeper than 20 ft/ 6m because of their general configuration and need more room to operate. Open bottom bags can also lose air due to rocking back and forth while on the surface when in rough water, known as “burping”. Retrieving anything submerged with this style bag has to be done in a manner allowing for quick hook up to recovery equipment located on a solid foundation when the submerged vessel breaks the surface of the water to limit the chance of losing the recovery due to the bag “burping”. The biggest advantage of the open bottom cushions is the ability to build very large recovery cushions with lower costs providing for a more cost effective cushion when dealing with greater lift capacity cushions.
The enclosed pillow style cushion offers a less volatile cushion due to the air being trapped inside so it only vents when either the relief valves open or divers pull on the ropes attached at the relief valves to open them manually. Many sizes are available covering a wide range of lift capacities. These are ideal for recovering vessels in shallow water such as lakes and rivers.
The boulder bags for very shallow water, salvage tubes for long sided hull or similar, propeller bags and personal floats are all used more for specific type recoveries and need to be discussed with one of our staff for proper application.