A few aspects are unique for ships and are therefore discussed here. For instance, operators could in special cases need a console at which work can be performed both sitting down and standing up, in order for the bridge personnel to keep a good lookout; thus, special consideration must be given to console and chair design. Alternatively, on some ships, typically high-speed craft, all work can and must be performed sitting down, necessitated by the often violent motions of the vessel in bad weather.
Another consideration is that work on the bridge is 24 hours a day, 7 days a week, daytime and night-time. Thus the displays and instruments must afford the dual function of being clearly readable in bright sunlight while also not disturbing night vision during darkness. The number of operators can vary from one or two, to (at times) up to five or more. During normal sea voyages the bridge crew may consist of one nautical officer and at times of darkness or low visibility, a lookout. When manoeuvring in restricted waters or port areas, the bridge has to accommodate at least a master, a pilot, perhaps two nautical officers, and a helmsman. This places high demands on both workplace design and procedures to make sure all team members can access relevant information and necessary controls at all times.
Even though ergonomic guidelines exist, they should always be considered in context. It is crucial to know about the functions to be performed in the ship control centres. An example of a bridge workplace is shown in Figure 9.1. This probably works well when manoeuvring normally and looking forward, but we see how it does not work well when manoeuvring close to a towering oil rig. One person manoeuvres the ship while the other is keeping a lookout. Ergonomics of both working positions are less than perfect. The position and posture of the lookout is evidently poor; the controller has an overextended elbow and obviously cannot see all he needs to see.