What it is
SeaVectors caches charts automatically as you browse, so the areas you've viewed stay available even without a connection. On top of that, you can download 14‑day marine forecasts — rain, wind, waves, tides, and currents — for the visible map area before you leave, so they stay available offshore where cellular or satellite coverage is limited. The Storage Management screen (and the Chart Download Manager) let you see your cache breakdown and clear local data anytime.
Want to prepare charts and forecasts before leaving coverage so they are ready when you need them?
The 30-day free trial includes the complete experience, so you can evaluate SeaVectors with your own routes and equipment before deciding whether to subscribe.
- Download SeaVectors on the App Store
- Get SeaVectors on Google Play
- Not ready to install? Open the lightweight web chart for a quick preview.
Why it matters on the water
Offshore, in a marina dead zone, or on a phone with no signal, you still need your chart and your forecast. Chart coverage builds up passively from wherever you've panned, and now a single download can bank two weeks of weather, tide, and current predictions for a whole trip area — so a loss of signal doesn't cost you the conditions.
How offline caching works
- Automatic — every area you view downloads and caches. "Charts you view are saved automatically."
- Persistent — cached tiles stay on device and render with no connection.
- Passive coverage — the more you browse an area (on WiFi/data), the more of it is available offline.
To prepare for a trip, pan and zoom over the whole route area while you have a connection. That pre‑loads the tiles so the entire passage is available offline.
Offline weather, tides & currents (download before a trip)
Beyond chart tiles, SeaVectors saves marine forecasts for offline use:
- Automatic — any forecast you load on the map is saved as you go. At detailed zoom, every tide/current station shown on the map automatically downloads about two weeks of predictions.
- Bulk download for a trip — use "Download forecasts for visible map" to save the whole visible area at once: up to 14 days of hourly rain, wind, and wave forecasts on a reusable grid, plus tide and current station forecasts. It processes a batch at a time (run it again for the next batch if the area is large), and tells you how many weather locations and stations are in view before you start.
- Offshore‑ready — saved forecasts render with no connection, so your weather, tides, and currents stay available when cellular or satellite is limited or gone.
How to: open the weather/forecast download control, confirm the Forecast download area (the visible map), and tap Download forecasts for visible map. Watch "Saving forecasts for offline use…"; when it's done you'll see how many were saved. Clear them later from Storage Management alongside your cached charts.
Manage storage
Open Settings → Chart Download Manager / Storage Management to:
- See the breakdown — how much space cached charts (and other data) use.
- Clear local data — free space by removing cached charts when you need to.
- Review offline coverage alongside your other data (Offline Maps in My Data — module 14).
Tips
- Before departure, on WiFi, slowly pan your whole planned route (and alternates/bailouts) at the zoom you'll navigate at — that's your offline prep.
- If the app is using a lot of space, clear the cache in Storage Management; areas re‑cache next time you view them on a connection.
- Cached charts + a recorded track + saved markers means a fully self‑contained trip with no signal.
- Before heading offshore, run the forecast download for your trip area — two weeks of rain/wind/wave and tide/current data that survives losing signal.
Troubleshooting
- "No chart available" offline → You never viewed that area on a connection, so it isn't cached. Pre‑load it next time you have signal.
- App using too much storage → Clear the cache in Storage Management; it rebuilds as needed.
- Charts look stale → Cached tiles are snapshots; reconnect and re‑view to refresh an area.