A ship is comprised of a number of Systems; each system has a specific purpose and it can either operate alone or form a component part of a larger system. A System is a combination of interacting elements (human and/or machine) organized to achieve one or more stated purposes.

The increasing reliance upon complex systems in merchant ship operations places certain demands and constraints on the human element, not least in terms of the competence of the user and of the organisational and physical environment in which he/she is required to operate.

The human element is a critical feature of all aspects of ship or system design and operation. User-input is essential to ensure that the operational parameters and the layout, crewing and procedures for the operation of shipboard systems are being optimised for the specific role or trade of the ship.

Those who are involved in the design, build and updating of ships and their systems and in their operation need to be aware of the problems associated with onboard operations not only in terms of workplace design but also in respect to crew habitability and the education and training needs of the seafarer.

Human-Centred Design (HCD) focuses on making systems usable. It is the process of systematically applying human factors and ergonomics knowledge and techniques to minimize human error, enhance effectiveness and efficiency, improve human working conditions, and counteract possible adverse effects of use on the health, safety and performance of the mariner.