The complexity corresponding to the industrial projects and their management are concepts whose interest is increasing. The structural complexity derives directly from the main characteristics of complex systems, that is, many elements that interact, resulting in this structure of great importance in engineering projects. As well as in today’s world, the attempts of organisations to be competitive tend to increase differentiation (both horizontal and vertical) and interdependence. The final result will be to increase the complexity of the organisation. All this leads to the current interest to deepen the study of this concept. In this research, a review of the state of the art of the concept is made and a theoretical framework is constructed to establish and justify the dimensions of complexity in engineering, focussed on the naval-shipbuilding. After the discussion of an index of technological complexity adapted to the naval shipbuilding, starting from the integration of the knowledge derived from the development of the F-100 frigate program, a novel methodological process is presented to assess two key aspects in the complexity of these projects; organisational complexity and technological complexity. Finally, the case study of the frigates programmes developed by Navantia Shipyards for Spanish (F-100, F-105), Norwegian (F-310) and Australian (AWD) navies is presented and studied. From the fact those frigates are similar products developed between the 90s and the 2010s, the technological complexity could be assumed invariable and the increment of projects structural complexity is quantitatively studied through the analysis of organisational complexity by clustering techniques and complexity indicators of statistical network analysis. The frigates complexity evolution and its assignable causes are estimated and identified. This methodology is proposed to be applied to naval-shipbuilding projects.

与工业项目及其管理相对应的复杂性是人们越来越感兴趣的概念。结构的复杂性直接源自复杂系统的主要特征，即许多相互作用的元素，因此这种结构在工程项目中非常重要。与当今世界一样，组织进行竞争的尝试往往会增加差异化（横向和纵向）和相互依赖性。最终结果将是增加组织的复杂性。所有这些导致当前对加深对该概念的研究的兴趣。在这项研究中，对这一概念的最新技术进行了回顾，并建立了一个理论框架来建立和论证工程复杂性的维度，重点是造船业。在讨论了适合海军造船的技术复杂性指标之后，从整合从F-100护卫舰计划的发展中获得的知识开始，提出了一种新颖的方法流程来评估这些复杂性的两个关键方面项目；组织复杂性和技术复杂性。最后，介绍并研究了纳万提亚造船厂为西班牙（F-100，F-105），挪威（F-310）和澳大利亚（AWD）海军开发的护卫舰计划的案例研究。从这些护卫舰是90年代到2010年代开发的类似产品这一事实，通过聚类技术和统计网络分析的复杂性指标对组织的复杂性进行分析，可以假定技术复杂性不变，并通过定量研究项目结构的复杂性。护卫舰的复杂性演变及其可归因的估计和识别。建议将该方法应用于造船项目。