Undersea riser structure

Claim 1

An undersea riser structure in an ocean comprising: a base fixed to the ocean floor; a vertically disposed hollow rigid post fixed to said base; a plurality of fluid conducting pipes fixed to said base; a riser that is attached to said base and rises towards the surface of the ocean; a rigid tubular column fixed to the lower end of said riser for sliding over said post; a plurality of fluid conducting pipes carried by said risers; a J-shaped tube fixed to said base with one end disposed within said post and the other end disposed outside of said post; a wire rope threaded through said J-shaped tube and having one end extending to the ocean surface and the other end connected to the interior of said tubular columns to allow the column to slip over said post as said rope is pulled at the surface; and first and second means for rotating the riser on a vertical axis as said riser is being lowered to said base so that said pipes in said riser are aligned with preselected pipes in said base before the respective pipes come in contact, said first means is disposed on said risers, while said second means is disposed on said base. 2. The structure of claim 1 wherein: said fourth means includes a lug protruding radially from said column; said fifth means includes an alignment plate disposed on said base spaced from said post and oriented substantially normal to a radius extending from the axis of said post; and said alignment plate having a V-slot for engaging said lug as said riser is being lowered.