The power budget is an important issue for autonomous vessels. Power is used for navigation (autopilot and actuators) and to power sensors, dataloggers and communication.  The Sailbuoy is designed to use very little power. The internal autopilot battery pack holds enough energy to navigate for 6 months without charging. Not being dependent on solar power for navigation, the Sailbuoy is an attractive platform for high latitudes where solar power is limited. To conserve energy the sensor payload can be in a low power state until the Sailbuoy arrives at the area of interest or until the payload batteries are recharged by the solar panels. This is a unique feature not found on other autonomous vessels.