Diver and crane operated Airlifts
MMC has a range of airlifts, these are used to excavate or to suck small objects, sand and mud from the seabed and to transport the resulting debris upwards and away from its source. They are sometimes referred to as suction dredgers or underwater hovers.
A controllable compressed air supply is pumped from the surface through a surface controlled manifold to the lower end of the airlift where the compressed air is injected into the bottom of the pipe to let the resulting bubbles of air rise higher, the air expands and pulls or sucks the excavated material or debris up and away from its source.
The diver also has a control valve on the airlifts so to have full control of any excivation.
Ejected debris can be either cast off (as in simply removing overburden) or collected in a mesh cage for inspection (as more often is the case in nautical archaeology).
All Airlifts are supplied with certified and pressure tested air lagging, CE and serial marked whip checks rated to one tonne.