This chapter provides an introduction to ship structures and includes descriptions of structural arrangements of the most important types of merchant ships and the properties of the materials used. This is followed by a discussion of the need to consider ship structures at different levels of analysis (top-down approach). The role of structural modelling, and in particular modelling applicable to global strength, is described. In the second part of the chapter an overview of current practice in ship structural design is presented, in which similarities between merchant and warship structural design are highlighted. The role of classification societies is described as well as that of the IMO Goal-Based-Standards. A comparison of classification society rules follows. The role of computer-based techniques is discussed. In the last section recommendations for good practice in ship structural design are provided.

We present an overview of the role, benefits, and drawbacks of theory in scientific research, particularly in the social and behavioral sciences. We discuss what theory is and what it is not. We also focus on some key elements of theory such as its ability to explain phenomena at multiple parallel levels of analysis. Evolutionary theory is offered as an example that illustrates the importance of conceptual integration across different disciplines. We further describe the key characteristics of good theories, such as parsimony, depth, breadth, and coherence (both internal and external), and we encourage the use of “coherence stress-tests” to help refine theory. We then discuss 4 advantages and 10 disadvantages of using theory in social and behavioral science research. Finally, we suggest conceptual tools and provide a list of recommendations for theory-driven research. We hope this chapter will help in the complex pursuit of improving research practices in the social and behavioral sciences.