We do a lot of buoy deployments and recoveries onboard the Thomas G. Thompson. These are not navigational buoys but rather scientific moorings.
The first thing is to find the buoy. Sounds simple, but many times they are missing or half sunk as a result of being struck by a ship or something.
Then we slowly approach and hand a special transducer over the side and trip the acoustic release. The release basically drops the anchor and the buoy and mooring line float free.
We lead the winch wire or retrieval line over the hanging block on the A-frame and lead it around the starboard side of the ship. A recovery hook is attached to the winch line and stuck on a pole that can be held out over the side. At this point, the captain manuvers the ship to the buoy to begin the recovery.
Once the hook is attached, the ship slowly moves forward and leads the buoy around the stern while the deck gang mends the winch line around the back of the back of the ship. We tow the buoy for a little while to stretch out the mooring line and keep it from getting fouled.
Once it is trailing nicely astern, we haul in on the winch and bring the buoy to the stern where we can attach tag lines and control to buoy when it comes aboard.
Then using the A-frame and winch the buoy is brought up on deck. The mooring line is stoppered off to the deck and the buoy is broken off from the mooring line. The buoy is then moved out of the way with a deck crane and secured.
The winch line is then attached to the mooring line and reeled in to complete the recovery. Often there are instruments attached on the line that we must stop and remove. Depending on the depth and complexity the recoveries can take from 2-7 hours to complete.
We then take them to a pier somewhere to get serviced / repaired for a future redeployment.