Interior Design of Cruise Ships: A Smart Materials-Driven Approach

Before defining the objectives and methodology of my doctoral research, it is important to understand the context in which this proposal was developed. We are in the middle of June 2020, three months after the achievement of the Master Degree in Nautical Engineering. In that situation, the results of a two-year project process were presented, related to a catamaran for passenger transport. This study allowed me to get ad advanced know-how related to the design spiral of a commercial vessel, both from an engineering and architectural point of view, compliant with strictly regulated comfort and safety criteria. This is the first reason that motivated me to stay within this sector, even though the cruise ship, compared to a waterbus, has a significantly greater number of passengers and crew, as well as a complex tourist itinerary and a framed range of services and entertainment facilities; a situation that goes well beyond the regular short and medium-range travel service which can help to avoid the congestion of the in-land public transport. To better understand the dynamics involving the design and operation of a cruise ship, which can be classified in terms of functions and scale of representation as a small urban centre, I have introduced the milestones which, from a historical point of view, have characterized the evolution of cruise tourism and the stylistic features of passenger ships from the 19th century (appearance of the first travel experiences) up to the present day. This actual historical moment bears the signs of what happened in 2020, the year in which the research proposal was conceived, during the Covid-19 emergency. The situation led, in addition to a high number of victims, to a paralysis in all sectors linked to the spheres of material production and social interaction of men. I wondered several times about the impact of this scenario on the design paradigm. Food for thought has originated from the analysis of the first pandemic episode outside of China, which just occurred on board a cruise ship, the Diamond Princess, engaged in a roundtrip cruise in the South of Japan at the end of January 2020. Covid-19 was a challenge added to the already complex systemic organization of on-board operations, worsened by the fact there were no methodological processes capable of dealing with an emergency of this type. During the first stage of the research activity I had the opportunity to come into contact with the Captain of the ship, Gennaro Arma, who allowed me to fully understand the situation through the point of view of someone who found himself managing a similar emergency firsthand. The ship constituted a closed control volume which allowed me to identify what could be the main propagation vectors of the virus through the application of a technique called FMEA (Failure Mode and Effect Analysis), which simultaneously considers possible design failures and process, their likelihood of being detected, and the frequency and severity with which they might occur. The motivation that led me to a comprehensive approach involving smart materials and technologies was driven by the desire to explore how scientific solutions and evidence are actually implemented and how they could be integrated into the overall design framework, resulting in increased levels of comfort and safety on board. Brainstorming activity started with an analysis of the materials currently applied on board, specifically in the living areas of passengers and crew; it will be presented as a global bill of materials including all the assemblies related to walls, ceilings, flooring, windows and doors, furniture and decorative elements. This activity has been possible also thanks to the attendance of two important fairs held in London and Hamburg related to the cruise industry sector. Types of materials that are rated as traditional and high-performance, chosen in terms of mechanical resistance, durability, lightness, corrosion resistance, temperature, and other physical properties that depend on the molecular arrangement and the thickness/shape within which they have been applied. This brings to a possible application of smart materials, where external stimuli induced by electric, magnetic, mechanical and thermal force fields, as well as variations in environmental parameters of temperature, pH, humidity, brightness, noise and the possible presence of harmful substances give rise to an active and reversible response which causes variations in intrinsic properties as well as a change in their structure, composition, function or form. Alongside them, for example, photochromic and thermochromic materials offers interesting possibilities for interaction with the surrounding environment, with surfaces capable of modulating the passage of light and the thermal control of internal environments. Self-healing materials, on the other hand, introduce new perspectives for maintenance and durability on a small scale (i.e. piping), allowing the autonomous repair of small superficial damages over time. Potential applications include photocatalytic finishings systems with self-sanitizing properties, as well as fabrics with antibacterial and water-repellent properties. It is possible to create devices integrated with sensors and actuators capable of reacting automatically, monitoring the state of a system (from the point of view of vibrations, thermal and light variations) and detecting specific environmental and human parameters. This design attitude focused on a case study of particular relevance, from an architectural point of view, for the ship, namely the cabin module. Multiplied thousands of times, accommodation areas cover most of the volume on board. Three standard cabin typologies are considered: interior, balcony and ocean view, which are typically installed on board as prefabricated units. I tried to understand how the application of smart and high-performance solutions could contribute to improving the technical specification of the same in terms of an overall analysis of their performances, starting from boundaries (wall, ceiling, floor panels) and related insulation analysis and the connection with the ship's deck, with consequent problems of noise and vibration transmission. It has been possible to determine the current state of the art through the analysis of specific patents currently implemented in the construction of cabins. Particular attention has been paid to the compliance of a proper degree of fire resistance and an optimized weight/thickness ratio (i.e. aerogel, vacuum panels). As concerns air quality, solutions capable of guaranteeing a good level of healthiness and humidity control were analysed, especially in wet units. An extensive insight relating to the topic of sustainability is aimed at creating a theoretical itinerary capable of understanding what tools are required to guarantee eco- and biocompatibility of the products applicable on board. Finally, a foresight addressed to a possible integration of advanced solutions is provided from the world of Project Management, related to the concept of quality as a parametre that should not be controlled, but rather carefully considered right from its concept design phase. In this context, Robust Design method by the Japanese engineer Genichi Taguchi has been introduced. With its application, products and systems can maintain constant nominal performance rates and quality despite the variations and uncertainties that may occur during their lifetime. It is a proactive approach to design that involves the use of empirical techniques like Design of Experiments (DOE, exposed in the closing part of the dissertation), together with computer simulations and statistical analysis. In this regard it is important to understand how many and what the identifiable variances are capable in the integration of materials that are as fascinating in their application as they are complex in their design and production.