The designation included purpose-designed passenger ships, notably the various types denoted by the M-class designation, but it was also included ships using converted freighter hulls. Luxury liners were regarded as a subtype of the even broader passenger liner classification. They often carried fewer people than the smaller SSP type, offering spacious cabins and impressive recreational areas on longer voyages. However, some luxury liners, like the famous Kuari Princess, were quite sizable vessels with accommodation and facilities for thousands of people.