Here is more about Prelude FLNG. It is 488 metres long, 74 metres high, and rises 105 metres above the water line. Unpowered, it is towed into position by oceangoing tugboats, then tethered to the sea floor by chains and connected to well head equipment by flexible pipes. It is designed to be able to ride out a category 5 cyclone, and has the ability to “weathervane” into the wind.