The first Jack-Up to be employed in the offshore oil- and gas industry was the 12-legged GUS-I built in 1954 by the LeTourneau company, an engineering and construction company specialized is the design of earthmoving machinery. The rather awkward design, employing a large number of cylindrical legs, was quickly followed by a lattice-leg Jack-Up which has close resemblance to the vast majority of Jack-Ups designs used nowadays. They are shown With the surging oil demand due to American prosperity after WWII the development of the Gulf of Mexico in terms of oil production grew rapidly. This growth was accompanied by developments in the Jack-Up market where the triangular three lattice-leg design was rebuilt and improved by LeTourneau. The development of the North Sea started to take shape in the 1970’s which was accompanied by a further growth in need for MODU units like Jack-Ups. More companies were offering rig designs in order to take a share in the growing MODU market. As the reserves in both GoM and the North Sea started declining towards the end of the 90’s the industry was pushed to greater water depths and harsher environments. This called for the latest generation of MODU Jack-Up designs, specially designed for deep water harsh environment applications.