1. Field Of The Invention
The invention pertains to the field of buoyant objects and more particularly to a buoy with a variable buoyancy.
2. Background Of The Invention
Submerged vehicles often have a need for above surface communications. Such a need, for example, exits when the submerged vehicle does not know its exact location and wishes to access the Global Positioning System satellite to obtain a position fix. To establish a communication link with the satellite it is necessary for the submerged vehicle to send an antenna to the surface with a link to the submerged vehicle. This is accomplished by placing the antenna in a buoy having sufficient buoyancy to ascend to the surface. These buoys are relatively large and, when stored in the cramped submerged vehicle, occupy much needed space.
An alternative to storing the buoy in the vehicle is to tow the buoy at the end of a tether coiled within the vehicle. As the tether is uncoiled the buoy commences its ascent to the surface. The size of the buoy, however, generates appreciable drag on the vehicle, seriously effecting its maneuverability.
It is an objective of the current invention to provide a buoy with variable buoyancy which is sufficiently compact at the submerged depth of the vehicle to permit convenient internal storage, or if towed to present little drag on the vehicle.