Angela Greenfield Jun 30, 2012:

from my link above: After preloading, the jacking system is used to raise the entire barge above the water to a predetermined height or "air gap", so that wave, tidal and current loading acts only on the relatively slender legs and not on the barge hull.
Modern jacking systems use a rack and pinion gear arrangement[2] where the pinion gears are driven by hydraulic or electric motors and the rack is affixed to the legs.

Angela Greenfield Jun 30, 2012:

But of course! Stupid me. Can you post your answer, Svetlana?

svetlana cosquéric Jun 30, 2012:

jacking system? http://www.fng.com/jacking-system

Angela Greenfield Jun 30, 2012:

A bit of reading on Jackups: http://en.wikipedia.org/wiki/Jackup_rig

Angela Greenfield Jun 30, 2012:

I don't know what this unit is called, but it's a part of a Jackup - a self-elevating rig that has movable support legs. Maybe if you look them up, you'll find the term.