Fourth substitute
ICS · Fourth substitute
In short: A curiosity: the fourth substitute does not belong to the civilian set of the International Code. The full code is 40 flags: 26 letters, 10 numeral pennants, 3 substitutes and the answering pennant. The fourth is met in naval signalling, where there are more flag sets and repetitions.
In plain English
A curiosity: the fourth substitute does not belong to the civilian set of the International Code. The full code is 40 flags: 26 letters, 10 numeral pennants, 3 substitutes and the answering pennant. The fourth is met in naval signalling, where there are more flag sets and repetitions.
Where you will really see it
You will not use it in merchant shipping; we show it for completeness because it appears in naval signal tables.
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).