This article attempts at assessing the feasibility and validity of adjusting the two-stroke diesel engine to be fuelled by liquefied natural gas (LNG). It discusses a set of modifications introduced onto one of the ships carrying liquefied natural gas. These changes consisted in adjusting the engines of the main drive so that they can be fuelled by gas. This has been achieved by the modification of the cylinder head and fuel supply installation. Parameter results of the modified engines obtained during sea trials have been presented. Both advantages and disadvantages resulting from gas combustion have been pointed out. Ultimately, the authors of this article assess the applicability of this solution to other LNG carriers.