Flag Hoist Composer
Type a message and Halyard builds a vertical International Code of Signals hoist. Decode mode lets you tap flags and read them back.
iPhone and iPad App ยท v1.1
Halyard
Compose maritime flag hoists, decode signals, drill semaphore, and use Signal Deck to practice routine, caution, and urgent hoists.
Signal Deck
Version 1.1 adds a training report for every hoist: flag count, word breaks, phonetic coverage, urgent/caution notes, and a practical drill.
Semaphore, Morse, Phonetics
Study semaphore positions, NATO/ICAO phonetics, and Morse references with audio/haptic practice for supported characters.
Offline Reference
Source links are included in Quick Reference. The app is for training and reference only; real marine operations should follow current official publications.
Private by Design
No account, no analytics, no tracking, no third-party SDKs, and no network required for core use. Photo-library permission is requested only if you save a generated hoist image.
Last updated June 27, 2026.