Offshore anchoring methods and systems

A method of temporarily anchoring a mobile offshore drilling unit at an offshore drilling site, the method comprising:

• laying out a plurality of anchoring assemblies at a sea floor, each anchoring assembly of the plurality of anchoring assemblies comprising a connection unit which is laid out adjacent to the offshore drilling site, an anchor line which extends away from the offshore drilling site, and a sea floor anchor which is connected to the anchor line at a distal end thereof;
• bringing the mobile offshore drilling unit to the offshore drilling site;
• successively for each respective connection unit,
• operating a dynamic positioning system at the mobile offshore drilling unit to move the mobile offshore drilling unit to a position substantially vertically above the respective connection unit,
• lowering, from the mobile offshore drilling unit, a drilling unit anchor line comprising a connection member so as to engage the respective connection unit, and
• connecting the drilling unit anchor line with the respective anchoring assembly via the connection unit and the connection member;
• and
• tensioning up each drilling unit anchor line from the mobile offshore drilling unit so as to anchor the mobile offshore drilling unit at the offshore drilling site via the plurality of anchoring assemblies.