Cell coverage ends before the water does. Helm is built so that the moment you lose signal is not the moment the app becomes a blank screen.
Coverage is divided into 161 downloadable packs. You take the water you actually run and leave the rest, so you are not waiting on a multi-gigabyte download for a country you will never cross.
| Feature | Offline |
|---|---|
| NOAA charts | Yes, from the downloaded pack |
| Depth against your draft | Yes |
| Route planning | Yes |
| Anchor alarm | Yes |
| Track recording and logbook | Yes |
| Tides | Yes, predictions are computed locally |
| Live weather and AIS | No — these need a connection by nature |
Downloads run in the background and resume if they are interrupted, so a pack that stalls at the dock picks up where it left off rather than starting over. Helm checks you have the disk space before it begins.
Download the packs for your area before you leave the dock. Once you are out of range there is nothing to fetch.
Offshore is the obvious case. The less obvious one is inland: many lakes have no usable coverage a few hundred metres from the ramp, and that is exactly where an unfamiliar bottom and a low water year cause problems.
It depends on the area and how much detail it carries. Helm shows the size before you download and checks that the device has room.
Yes, and Helm asks for confirmation first so you do not lose coverage by accident.
Yes. It runs on GPS, which does not need a connection.
Helm Boating