Lengthening and Deepening the "ESSO SWITZERLAND"

Abstract

The "ESSO SWITZERLAND", which was built two years ago, was recently enlarged from a 35,000 DWT class tanker to 49,000 DWT in our shipyard to improve operational efficiency. A newly built 80 ft. midbody with two tanks was added, and, besides this, not as in a usual jumboizing, the depth was increased by raising the upper deck 9 ft. To lengthen vessel is often undertaken and is not especially noteworthy, but to deepen it on such a large scale seems to be the first attempt in the world. This report mainly describes the procedure used in deepening the ship. The method used consisted of cutting the hull abaft the midship bridge for the newly built midbody, and of horizontally cutting the hull at 12 ft. 8 in. below the upper deck. The lifting power of a floating dock was utilized to remove the upper part of the hull by hanging it on the walls of the dock. The upper part was replaced by cranes after hull deepening blocks had been installed.