Jackup rigs or self-elevating units are so named because they are self-elevating with three, four, six and even eight movable legs that can be extended (“jacked”) above or below the hull. Jackups are towed or moved under self-propulsion to the site with the hull lowered to the water level, and the legs extended above the hull.
When the rig reaches the work site, the crew jacks the legs downward through the water and into the sea. This anchors the rig and holds the hull well above the waves. Because the rig is a sea-going vessel, it is subject to the same rules and regulations as ships are.
The legs are what give the jackup its name. They can be raised and lowered on ratchets in a process known as jacking up or jacking down. During jacking up, the legs go down and the rig goes up. During jacking down, the legs go up and the rig goes down until it floats on the surface of the water, then the legs continue to travel up until they tower above it.
The verticals that form the outside of the lattice are called chords. Legs can have a square cross-section with four chords, or a triangular cross-section with three chords. The legs are operated by jacking motors, which drive cogs that move notches on the jacking chords up and down. This is known as a rack and pinion system. The rack is the series of notches on the chord and the pinion is the gear whose teeth interlock with the rack.
It may be clear that when lubrication on board of such platforms, this is preferably done with high-tech lubricants. The conditions under which the racks of a lifting platform must serve require
a specific grease that is more environmentally friendly, withstands extreme high loads, is highly water-resistant and offers optimum protection against wear.
In collaboration with its specialist supplier Lubricant Consult GmbH from Germany, Van Meeuwen has developed a new generation biodegradable lubricating grease for these specific applications where biodegradability plays a very important role: Lubcon Grizzly Grease Bio 1-1000. Other applications where Grizzly Grease Bio 1-1000 can be used very well are wire ropes, bearings, bushes,
cylinder and piston units and guideways.