Litton Avondale Industries delivered the Polar Endeavour on April 30, 2001, the first of five Millennium Class double-hull crude carriers. The tankers are being built to meet or exceed existing and proposed environmental regulations and will set new standards for innovation and environmental protection. The inner and outer hulls are separated by a distance of 10 feet, which exceeds regulatory requirements. This design allows for greater protection of cargo tanks and limits oil release if damages reach both hulls.

The crude carriers are 272.69 m long by 46.2 m wide by 26.3 m deep (894.7' x 151.6' x 86.29'). The ship's total capacity of just over one million barrels of oil will be carried in 12 cargo tanks. In addition to being built with double hulls that exceed regulatory minimums, the tankers incorporate double, independent engine rooms, twin propellers and twin rudders for greater maneuverability. The Millennium Class vessels will have all cargo, fuel and lubricating oils isolated from the ship's side by ballast tanks or void spaces. The vessels will meet pending air emissions regulations for engines. The ships are also being painted with tin-free, anti- fouling paint in anticipation of proposed regulations.