Sealift, a company created by Frontline to operate oil-rig transporters, raised $180 million in a share sale in which its parent bought a 33 percent stake. Frontline $167 million profit selling six single-hulled oil tankers to the Sealift unit for conversion into oil-rig transporters.

Frontline and other owners are racing against a 2010 United Nations deadline on using tankers with only one layer around their cargo tanks, known as single-hulls. By converting those ships to alternative uses, Frontline will be able to extend the vessels? working lives instead of having to sell them for scrap.