- Channels 16 and 06
- Every survival craft VHF works on channel 16 (156.800 MHz) and at least one other simplex channel. Channel 06 is the on-scene channel for search and rescue, and for talking to SAR aircraft.
- Power
- At least 0.25 W. A set stronger than 1 W must have a switch to cut it to 1 W or less. Use low power when the other station is close: it saves the battery.
- Range
- VHF is line of sight. From a liferaft, low to the water, a handheld reaches a ship about 5 nm away. The ship, with more power and a higher aerial, can usually be heard much further off. Keep the antenna upright.
- Sealed emergency battery
- A non-rechargeable battery kept for emergencies, sealed so you can see it hasn't been used. It gives 8 hours at full power with a duty cycle of 1:9 and has a shelf life of at least 2 years. Check the expiry date; once the seal is broken, replace it.
- Rechargeable battery
- For tests and routine use, so the sealed battery stays unused. Keep it charged.
- Built for the raft
- Watertight to 1 m for at least 5 minutes, survives a 1 m drop onto a hard surface, works from −20 °C to +55 °C, usable with gloves, and coloured yellow or orange (or marked with a yellow or orange strip).
- Carriage
- SOLAS passenger ships and cargo ships of 500 GT and over carry at least 3; cargo ships of 300–500 GT carry at least 2. Stow them where they can be taken quickly to the survival craft.
- Switching on
- Check three things, in this order: squelch, then channel 16, then HIGH power.
- Squelch
- Turn it down until you hear the hiss, then up until the hiss just stops. Set too high, it cuts out weak stations, often the ones you need.
- Spare battery
- In an exercise or abandon ship, take the sealed spare battery with you. Leave it sealed and fit it only when the radio's own battery runs low.
- Channels 15 and 17
- On-board communication, at 1 W or less. Test with the bridge on these, never on channel 16.
- Talking
- Listen first. Press PTT, pause a moment, speak clearly, release and listen. In distress traffic, start every message with MAYDAY. Keep it short, and end with Over or Out, never both.