Every flag, light, buoy, cloud and signal, one glance away. A pocket field guide for sailors. Free, no account, no ads. Built for the moment on deck, not the classroom. Spot something, look it up, understand it, in a few seconds. When you want to go deeper, an Education tab gives you 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.