Don't venture offshore without your EPIRB
An EPIRB (Emergency Position Indicating Radio Beacon) is an effective alerting and locating device that is complusory for all vessels operating more than 2 nautical miles from the shore.
Once activated, the EPIRB transmits a signal for at least 48 hours and can be detected by satellites and aircraft.
From 1 February 2009, 121.5 MHz distress beacons are no longer detected by satellite you must switch to a 406 MHz distress beacon. Essential 406 beacon information is availalble from the Australian Maritime Safety Authority.