Abstract: A variable buoyancy buoy and method for deployment therefor can include a fixed buoyancy portion formed with a cavity and an enclosure. A pressure hull containing instrumentation can be place in the cavity, and a variable buoyancy portion that can be inserted into the enclosure. The fixed buoyancy portion can have a spar buoy configuration or a marker buoy configuration, and can further be formed with at least one opening to establish a path of fluid communication between the exterior of the buoy and the enclosure. The variable buoyancy portion can be a compressible bladder, or compressible foam, which can change form a maximum volume at the water surface to a minimum volume as the buoy descends towards stowage depth. The decrease in buoyancy facilitates retrieval of the buoy by an apparatus on the ocean floor.

Abstract: A self-stabilizing buoy and deployment methods can include a main body and a cage that can be attached to the main body. A ballast can be slidably positioned within the cage so that the ballast moves from within said cage to outside of the cage when the buoy is deployed. The cage can be formed with at least one slot. The buoy can include a locking mechanism to fix the ballast at the distal end of cage after deployment, which can include a locking head that can be fixed to the ballast and inserted into the slot, and at least one flexible cantilevered arm that can extend from the cage into the slot at its distal end. As the buoy is deployed, the weight of the ballast can be sufficient to urge the locking head past the cantilevered arm to fix and lock the ballast during buoy deployment.