Although often luxurious, ocean liners had characteristics that made them unsuitable for cruising, such as high fuel consumption, deep draught that prevented their entering shallow ports, enclosed weatherproof decks that were not appropriate for tropical weather, and cabins designed to maximize passenger numbers rather than comfort (such as a high proportion of windowless suites). The gradual evolution of passenger ship design from ocean liners to cruise ships has seen passenger cabins shifted from inside the hull to the superstructure with private verandas. The modern cruise ships, while sacrificing qualities of seaworthiness, have added amenities to cater to water tourists, and recent vessels have been described as "balcony-laden floating condominiums