Flag S (Sierra)
ICS · S code word: Sierra pronounced: SEE-AIR-RAH Morse: ···
In short: I am operating astern propulsion.
Single-letter meaning (Pub 102)
I am operating astern propulsion.
Morse sign
···
Dot = short sound, dash = long (three times longer). Hear it in the Morse translator.
In plain English
Engines going astern: the ship is braking or backing.
Where you will really see it
The same sense as three short blasts on the whistle under the COLREGs. S also has a special meaning as a landing-place signal for small boats with survivors (SOLAS).
Careful with sound
Signal S belongs to the group marked with an asterisk in the code: when made by SOUND it may only be made in compliance with the collision regulations (COLREGs). By flag or light there is no such restriction.
Related flags
Keep going
- All signal flags: the search box and the full grid.
- Interactive mast: build your own hoist.
- Single-letter signals cheat sheet A to Z on one page.
The single-letter meanings are quoted 1:1 from Pub 102 International Code of Signals (NGA, public domain); the plain-English explanations are our own. Flag graphics: signal-flag-images (Unlicense).