Best practice: when to provide physical switches
Consider that touchscreen displays:
lack tactile feedback
are sensitive to accidental touches
can be hard to use in adverse environmental conditions (rain, rough sea state)
can be hard to use when wearing gloves
may require additional touches (for example, using menus and page jumps) to reveal the required control button
may be hard to navigate quickly, especially in emergency situations, or by users unfamiliar with the installation
If the user needs to switch systems or equipment in response to urgent conditions, or repeatedly operate a switch while looking away from the touchscreen display, consider providing a physical switch in place of (or in addition to) a soft-button on a touchscreen.
Physical switches are also recommended when it is important that the switch location maintains the operator’s line-of-sight with the switched-equipment.
Some examples where provision of a physical switch is recommended:
operating the vessel’s horn
operating internal lighting positioned to illuminate bridge controls
operating an emergency stop feature (for example, to immediately stop a moving piece of equipment that is within the switch operator’s line of sight)