The First Substitute Flag is part of the International Code of Signals (ICS), which is an international system of signals and codes for use by vessels to communicate important messages regarding safety of navigation and related matters. The pictured flags are the most recent evolution of a wide variety of maritime flag signalling systems.
- Flag uses:
- Substitute for the first flag in this hoist. (International)
- Also "repeats" the first flag or series of flags in this hoist
- Absence of flag officer or unit commander (In port). (Navy)
- General Recall (Sailing Regatta)