Phone, Watch and Satellite: Offline, Battery, and SOS

A phone with a map app feels like a complete navigation system until the third day, when the battery is at 9% and the screen has gone dim in the cold. The fix is not a better app. It is a plan.

The phone

• Download offline maps and tracks before departure, turn off auto-update and background refresh, and test airplane mode — it is the single biggest battery saving available.
• Cold drains and shuts phones down. Keep it in an inside pocket, not an outside one. Carry a power bank and cable.
• A waterproof phone is not a dive-rated phone. If it floods, do not charge it — power it down and dry it first.
• Screen brightness, track recording, camera and drone control are the four biggest drains. Turn them on deliberately.

Watches and sports devices

• Charge fully before departure and carry the cable or clip. On long trips, plan one charge per day.
• GPS accuracy and battery life trade against each other; power-saving modes may reduce track frequency.
• A watch does not replace a map and compass. Learn contours and bearings anyway.

Satellite messengers and PLBs

• For remote or unserviced routes, a satellite messenger (inReach and similar) or a PLB is emergency communication, not a chat tool.
• Before you go: confirm the subscription and plan, register the emergency contacts, send a test message, and learn the preset messages and the SOS procedure.
• A PLB only raises an alarm — it cannot talk back. Register it as local regulations require.
• Satellite devices still suffer from sky obstruction, battery and weather. They supplement a trip plan; they do not replace one.

Emergency information

• Put emergency contacts, allergies and medications on the lock screen, balancing privacy against usefulness.
• Store offline: local rescue and police numbers, the insurer's assistance line, the agreed meeting point.
• Do not put all navigation and all communication in one device.