Signal Deck

SignalDeck is the essential training companion for mariners, naval cadets, offshore sailors, and maritime enthusiasts who want to master the International Code of Signals (ICS) flag system — the visual language of the sea.

Study the Full ICS Flag Set
Browse all 36 ICS flags — the complete 26-letter alphabet (Alpha through Zulu) plus 10 numeral pennants (0 through 9) — presented as beautifully rendered flashcards. Each card shows the flag's name, NATO phonetic pronunciation, and its official maritime meaning. Swipe through at your own pace, filter by letters or numerals, or shuffle the deck to keep every session fresh.

Three Drill Modes to Test Your Knowledge

Visual ID: A flag appears on screen. Can you name it before time runs out? Tap the correct NATO name from four options and build your streak as the pace intensifies.

Flag Bag: The challenge flips — you're given a NATO letter or name and must pick the correct flag from four choices. Perfect for cementing the visual recognition you've built in study mode.

Flag IQ: A memory match game with a nautical twist. Flip face-down cards on a grid to pair each flag image with its NATO letter or official ICS meaning. Choose Easy (4×4, letter cards), Medium (4×5, meaning cards), or Hard (6×6, mixed) — and earn your rating from Bridge Apprentice to Master Chief Signalman based on how few mismatches you make.

Built for Serious Learners
Animated flags rendered with authentic nautical proportions and a sea-breeze waving effect

Streak tracking with escalating visual feedback as your streak climbs

"Needs Practice" summary after every drill — instantly see which flags to revisit

Fleet Readiness Heatmap in your drill log — color-coded badges show your mastery level for every flag at a glance

Drill log that records every session so you can track progress over time

Timed pressure in Visual ID and Flag Bag mirrors the urgency of real-world flag communication

A Living Reference at Sea and Ashore
Whether you're preparing for a maritime exam, brushing up before an offshore passage, training cadets, or simply fascinated by the tradition of visual signaling, SignalDeck gives you a focused, distraction-free environment to drill the flags that matter.

Free to Start — Go Premium for Unlimited Access
New users get free drill sessions to explore the app. Watch a short ad to unlock another round, or upgrade to Premium for unlimited drills, no ads, and full access to every mode and difficulty tier.

The sea doesn't wait. Neither should your training.

Recent changes:
v1.0.57
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Bug Fixes

- Tablet (landscape) — Tutorial overlay alignment: Fixed an issue where the "How to navigate" and "Shuffle Mode" tutorial overlays appeared shifted to the right on tablets in landscape orientation. The overlay now correctly highlights the card and positions all annotations, labels, and buttons over the actual card area.