SeaCheck

SeaCheck is something I built for my own small-boat sailing — a deck-side companion to paper charts, not a replacement for them.

I use it for boat speed, coordinates, a quick chart position without going below, passage sketches, and anchor alarms. I'm sharing it in case another coastal sailor finds it useful. No launch, no support promise — use at your own risk.

NOT FOR PRIMARY NAVIGATION
Aid to navigation only. Not a certified chart plotter. Maps use OpenSeaMap / OpenStreetMap volunteer data and may be outdated. Always carry official, corrected nautical charts.

FEATURES
• GPS on chart — COG, SOG, bearing
• Passage planning, waypoints, GPX export
• Offline region packs (Wi‑Fi download)
• Anchor, arrival, and off-course alarms
• Track recording
• EN / DE UI

Free. No ads. No analytics. Data stays on your device.

Recent changes:
• Passage planning: zoom stays where you left it when adding waypoints (no more jump back)
• Chart downloads: other pack Download buttons no longer stay greyed out after the first pack
• Boat follow pauses while you plan on the chart, so GPS does not fight your pan/zoom
• Play quality: full R8 optimization, edge-to-edge cleanup, WebP splash assets
• Stability fixes for offline pack download locking

Navigation companion only — not a substitute for official charts and good seamanship.