Typically, when marine security teams deploy on-board a vessel, they take a RockSTAR device with them. Before the start of the transit the unit is turned on, and will start transmitting a position fix once per hour (or whatever the customer chooses).
Back at HQ, the customer uses The CORE to monitor the positions of all their teams/vessels.
In the case of an emergency, the RockSTAR unit can be used to alert HQ, using either the dedicated red button, or better using the messaging facilities to indicate the type of alert, and any other relevant details.
The RockSTAR's means of communication is completely separate from the vessel, so even if power is turned off aboard, the RockSTAR will continue to operate. It can be sent a command to go into 'stealth mode' which means that the screen and LED are turned off - the unit continues to operate as normal, but it looks as though the battery has run out - useful if compromised.