Between 80 and 100 engineers, technicians, labourers and hospitality personnel are currently working around the clock to ensure the smooth 24-hour running of the Sedco 711 oil and gas rig.
As well as drilling the sixth in what may be as many as nine dinner-plate sized-wells in the Corrib field, the rig is also their home while on duty.
Most of the staff work a two-weeks on, two-weeks off rotation in shifts of 12 hours. The work while they are on duty is intense and when they aren't on duty the main activities are watching TV and sleeping in cabins.
The rig, which stands about 550 metres - almost as tall as the Empire State Building - off the bottom of the seabed, is an imposing structure once aboard, with a maze of internal corridors linking living accommodation with a canteen and offices.
Looking out through the large windows of the control room it's hard to imagine you're not on a ship in the open seas.
Significant movement however is prevented by eight hefty chains attached to the four corners of the rig, which ensure it stays firmly where it should be - directly above a hole that is being drilled 3,000 metres into the seabed.
Currently there is only one Irish person on the rig - a female well engineer - with the majority of workers (mainly men) flying in from Aberdeen via a 70-minute helicopter flight from Donegal.
