
Spot it on the water
A light, buoy or shape
Ahoy is a pocket field guide for sailors. Ship lights, signal flags, buoys, weather and VHF. Free, no account, no ads.


Know this feeling?
A light on the horizon at night. Is it coming toward you?
Ahoy is built for the moment on deck, not the classroom. Spot something, look it up, understand it, in a few seconds.

A light, buoy or shape

Find it in a few seconds

And what to do next
A field guide for the moments you need an answer fast.
Identify vessels at night by their light pattern, shown from every angle as glowing schematic diagrams.
All 36 flags with their meanings, Alpha to Zulu, plus the phonetic alphabet.






Lateral and cardinal marks with the shapes each can take, plus the cones, balls and diamonds and what they signal.



The Beaufort scale with real sea-state photos, and clouds with what each one means for your weather.
2 Bft
6 Bft
10 BftSound-signal patterns for every condition, and ready-to-read VHF scripts: Mayday, hailing a vessel, radio checks.
Searchable sailing jargon, from abeam to windward.
The marks on a nautical chart, decoded: lighthouses, wrecks, anchorages, rocks and soundings, so the paper or the plotter reads at a glance.
Ahoy is built for quick lookups, but when you want to go deeper there is an Education tab.
Endless recognition drills, exam style: a light or a day shape appears, you name it, you learn. Ship lights and day shapes now, more on the way.



Sound familiar?
The captain gives an order. Did you catch every word?
Hey ๐ I'm Krzysztof, and I built Ahoy because I sail for fun and got tired of nodding along when the skipper pointed at a light or a buoy I couldn't name.
The apps I found wanted to turn me into a student, all flashcards and long courses. I just wanted something I could pull out on deck, check in a few seconds, and put away. So I built it.
My hope is that Ahoy makes you feel a little more at home on the water.

โThere's never enough learning at sea, and Ahoy is a brilliant way to keep at it.โ
โIt's never been easier to recall what I need for another safe adventure.โ
โWith Ahoy in my pocket, I feel as seaworthy as the boat I'm on.โ
Free & Pro
The whole guide is free wherever you have a signal. Ahoy Pro unlocks it fully offline, for out at sea where there is none.
| ย | Free | Pro |
|---|---|---|
| The complete reference guide | ||
| Training feed & recognition drills | ||
| No account, no ads | ||
| Works offline, no signal needed | โ |
Download free, then unlock Ahoy Pro inside the app. A one-time purchase, no subscription.
Everything you need to know about Ahoy.
Ahoy is free, no account, no ads. Go fully offline at sea with Pro. Download it and see.
Download on theApp Store