Well capping assembly and method of capping underwater well

A method of capping an underwater well comprising:

• deploying a capping structure into a body of water at an offset position from the underwater well;
• floating the capping structure with at least one buoyancy tank;
• submerging the capping structure;
• positioning the capping structure over the underwater well after the submerging, wherein the deploying and the positioning utilize first and second vessels attached to the capping structure with a plurality of mooring lines and the vessels remain on opposing sides offset from directly over the well to avoid placement of the mooring lines, the vessels and the capping structure at a surface of the body of water directly above the well throughout the deploying and the positioning;
• rigidly anchoring the capping structure to a sea floor surface;
• maneuvering a well cap structure in at least one direction with a capping frame that is operatively coupled to the capping structure;
• and
• capping a fluid flow from the underwater well upon operatively coupling the well cap structure to a wellhead structure.