Patent ID: 6210075
Filing Date: 2001-04-03
Classification: B63B,E21B

Abstract:
An offshore installation comprising:a buoyant spar which floats at the sea surface and can drift, and that has a vertical length that is a plurality of times greater than its average width, and having upper and lower ends;a subsea buoy which lies below the sea surface and above the sea floor and which can drift, said subsea buoy having upper and lower ends and having a tree, with said subsea buoy upper end and said tree being detachably connected to said spar lower end and with said subsea buoy being capable of being negatively buoyant to hang from said spar buoy and help keep said spar buoy vertical, and said subsea buoy being made capable of being made positively buoyant to float at an underwater depth when disconnected from said spar buoy;at least one riser extending from the sea floor to said subsea buoy.