ABSTRACT
Distress signal devices provide visual or audible signals in the form of either red flare or orange smoke or sound. Some devices provide both signals of red flare and orange smoke. The intensities of red flare and orange smoke densities vary in various devices. These are used for distress signalling or marker purpose. The basic aim of these devices is to convey distress message through red flare, orange smoke and sound. Essentially, it is a visual/audible means of sending SOS signals. The aim is to intimate that someone is in distress and needs help and indicates the location of distress for help. Orange smoke is chosen since it gives better contrast with grey/blue air and blue sea water while red flares for its better visibility due to its longer wavelength. The signals must be capable of conveying distress for day time or night time, though some are capable of distress signalling in both day time and night time. This chapter provides role and types of distress signalling devices used in air by air force men, used in sea by navy or merchant navy, used on land by ground personnel or troops. It also provides SOLAS (safety of life at sea) regulations for naval distress signals. References are given at the end of the chapter.
