In the case of cruise liners, aluminium superstructures are also installed. Sections made from this material have a weight advantage and enable higher superstructures than comparable ones made of steel. Thus, larger ships can be built, allowing larger numbers of passengers. The welding and cutting processes used to make the sections are similar for both aluminium and steel. However, the welding processes with aluminium require the use of inert gases. Thus, arc welding methods such as MSG welding (here, MIG welding) or laser beam welding are applicable, but not gas welding or flame cutting.