Spar disconnect system

In a spar-type offshore platform having a buoyant upper hull structure having an upper end supporting a deck and a lower end configured to receive a buoyant lower mooring module to which a plurality of mooring lines are secured, apparatus for detachably connecting the upper hull structure to the lower mooring module, comprising:

• a plurality of guide posts extending upwardly from the mooring module;
• a plurality of receptacles located on the upper hull structure so that each of the receptacles receives one of the guide posts;
• and
• a plurality of connection lines releasably secured between the upper hull structure and the mooring module.

A method of (i) removing a deck-supporting buoyant upper hull structure of a spar-type offshore platform from a detachable buoyant lower mooring module that is moored to the seabed and that is connected to a lower end of the upper hull structure by connection lines, and (ii) re-connecting the lower end of the upper hull structure to the mooring module, comprising the steps of:

• (a) disconnecting the connection lines between the upper hull structure;
• (b) lowering the mooring module relative to the upper hull structure, while the mooring module remains moored to the seabed;
• (c) moving the upper hull structure away from the mooring module while the mooring module remains moored to the seabed;
• (d) re-positioning the upper hull structure over the mooring module;
• (e) hauling the mooring module up toward the upper hull structure until the mooring module is engaged with the lower end of the upper hull structure;
• and
• (f) re-connecting the connection lines between the upper hull structure and the mooring module.