Sail Horizon

Sail Horizon is a sailing simulation built around the water. The sea is a spectral FFT ocean (three cascades, JONSWAP spectrum, foam from breaking crests) rendered on the GPU, so swell, chop and wind waves move the way they do at sea, and the yacht rides on exactly the waves you see: she heaves, pitches and rolls with the swell, heels under sail, rounds up in gusts and digs in at hull speed.

Pick your sailing area on a world chart: the coastline is the real one (Natural Earth 1:10m, public domain), cut into tiles and loaded for the 13 km square around the spot you click. Famous spots are one click away – the Nā Pali cliffs of Kauaʻi, the Virgin Islands over turquoise reefs, Cap de Formentor, Santorini's caldera, the chalk cliffs of Rügen, the Lofoten, Cape Town, the Whitsundays – or click anywhere at sea. Relief, vegetation, beaches, reefs and the colour of the water follow the region: Caribbean turquoise, Mediterranean blue, grey-green northern seas, fjords with snow.

The boat is the NEREID 37, a modern 11.3 m cruiser with twin wheels, fully articulated: rudder and wheels, boom and traveler, furling genoa, main with two reefs, gennaker, storm jib, the running rigging – and a skipper who stands at the windward wheel, leans into the heel, and walks to the mast or the winches when you reef or furl. Dolphins ride the bow wave, flying fish burst out ahead of a fast boat, gulls circle near the coast.

You control what a real crew controls: rudder, main and genoa sheets (with the ideal trim marked), reefing, furling, gennaker, storm jib, engine, autopilot and auto trim. Choose the conditions – calm, light breeze, choppy or storm – and the wind keeps shifting, gusting and trending while you sail. The coach on board explains the instruments, warns when you are overpowered, pinching, in irons or about to gybe, tells you when to reef and when to shake it out, and guides you round the marks.

Sail freely or race timed courses of 3 or 6 marks laid around your spot. The club leaderboard counts one thing: the log – every nautical mile you sail, anywhere in the world, adds up.

Best in a WebGPU browser (Chrome, Edge, Safari 26); other browsers get a simplified WebGL ocean.