LONDON (Bloomberg) ? Frontline Ltd., the world?s biggest oil-tanker operator by capacity, plans to spin off a ship-based oil-rig unit it?s creating as part of efforts to prolong earnings from single-hulled tankers after they are banned.

The company will spin off the business when it has reached ?sufficient size? through acquisitions and by converting some of its existing single-hulled vessels into platforms for pumping oil, known as floating production, storage and offloading vessels, or FPSOs, Frontline chief financial officer Tom Jebsen said yesterday.

Bermuda-registered Frontline in June last year spun off its Ship Finance International Ltd. shipowning unit and in December created Golden Ocean Group Ltd. to operate the company?s dry-bulk ships.

The splits were aimed at getting a higher combined value for the companies.