Sierra
Phonetic alphabet letter S.
Astern Propulsion: When a vessel displays the Sierra flag, it indicates that the vessel is moving in reverse, using its astern propulsion (reverse gear). This signal is crucial for alerting nearby vessels to the manoeuvrability and intentions of the displaying vessel.
Flag
Code Flag Sierra (S)
Nautical or signal flags are used at sea to convey messages over long distances. Only black, blue, red, white and yellow are used because these are the only colours readily distinguished at sea. Many different coding schemes have been used, but the International Code is the most common.
