Now on the App Store

Every light, flag and buoy, one glance away.

Ahoy is a pocket field guide for sailors. Ship lights, signal flags, buoys, weather and VHF. Free, no account, no ads.

Download on theApp Store
  • Free
  • No account
  • No ads
Ahoy showing a sailing vessel's navigation lights from four angles
A beam of light cutting across dark, foggy water at night

Know this feeling?

A light on the horizon at night. Is it coming toward you?

How it works

See it, name it, know it.

Ahoy is built for the moment on deck, not the classroom. Spot something, look it up, understand it, in a few seconds.

Step 01

Spot it on the water

A light, buoy or shape

Step 02

Open Ahoy

Find it in a few seconds

Step 03

Know what it means

And what to do next

Features

What's inside

A field guide for the moments you need an answer fast.

Ship Lights

Identify vessels at night by their light pattern, shown from every angle as glowing schematic diagrams.

Signal Flags & Marine Alphabet

All 36 flags with their meanings, Alpha to Zulu, plus the phonetic alphabet.

Buoys & Day Shapes

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

Weather

The Beaufort scale with real sea-state photos, and clouds with what each one means for your weather.

2 Bft
6 Bft
10 Bft

Sound & Radio

Sound-signal patterns for every condition, and ready-to-read VHF scripts: Mayday, hailing a vessel, radio checks.

VHF · CH 16MAYDAY

Dictionary

Searchable sailing jargon, from abeam to windward.

Abeam
Windward

Chart Symbols

The marks on a nautical chart, decoded: lighthouses, wrecks, anchorages, rocks and soundings, so the paper or the plotter reads at a glance.

Lighthouse
Wreck
Anchorage
Rock
52Sounding
Education

Train your eye

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.

  • Ship lights
  • Day shapes
  • Exam-style
Ahoy's endless recognition trainer feed
Ahoy's Education tab with recognition drills
Hands on a sailboat's wheel at dusk, looking down the deck to the sea

Sound familiar?

The captain gives an order. Did you catch every word?

Hey 👋 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.

Krzysztof Przekwas
Krzysztof Przekwas
“There's never enough learning at sea, and Ahoy is a brilliant way to keep at it.”
Gregory
Sailing instructor
“It's never been easier to recall what I need for another safe adventure.”
Justine
Occasional sailor
“With Ahoy in my pocket, I feel as seaworthy as the boat I'm on.”
Jacob
Crew member

Free & Pro

Free to use. Pro for the open sea.

The whole guide is free wherever you have a signal. Ahoy Pro unlocks it fully offline, for out at sea where there is none.

Free
$0
The full guide, always free
  • The complete reference guide
  • Ship lights, buoys, flags, weather, VHF
  • Training feed & recognition drills
  • No account, no ads
Download on theApp Store
For out at sea
Ahoy Pro
One-time
Yours forever, no subscription
  • Everything in Free
  • The whole guide, fully offline
  • No connection, anywhere on the water
  • A one-time purchase that supports a solo maker
Get Ahoy Pro
 FreePro
The complete reference guide
Training feed & recognition drills
No account, no ads
Works offline, no signal needed–

Download free, then unlock Ahoy Pro inside the app. A one-time purchase, no subscription.

Frequently asked questions

Everything you need to know about Ahoy.

Ready to cast off?

Ahoy is free, no account, no ads. Go fully offline at sea with Pro. Download it and see.

Download on theApp Store