World War II shipwreck reefs probed by manned submersibles
An expedition documented the sea life that has made these vessels, which haven't been seen since they sank in 1942, their home.
In July 1942, German submarine U-576 sank the freighter SS Bluefields during the battle of Convoy KS-520 off the coast of North Carolina.
The convoy fought back, though, and return fire from US Navy Armed Guard and an aerial depth charge attack sank the U-boat.
The vessels lay on the sea floor for decades as fish and other marine life moved in and made them home.More than 70 years later, in 2014, the wrecks were rediscovered and in August and September this year, the US National Oceanic and Atmospheric Administration and research partners went in for a closer look.
This is what they found.
Project Baseline's mini-sub Nemo prepares to dive.
During the very first dive of the expedition, scientists located and explored the German U-576. This was the first time since the submarine was sunk on 15 July 1942 that anyone had laid eyes on the vessel.
Here, the Nemo submersible shines its lights on the U-boat lying on its starboard side, showing the submarine's conning tower and the deck gun in the foreground.
The conning tower of U-576 as viewed from the mini-sub. Entry was gained to the U-boat through a watertight hatch located in the centre of the conning tower. The attack periscope can be seen in the near the back of the tower.
A video frame grab of the stern cabin of the SS Bluefields. Bluefields is intact and rests in 220 metres of water, only 180 metres from U-576.
Joe Hoyt, maritime archaeologist with the NOAA Office of National Marine Sanctuaries, documents the damage to U-576.
A video frame grab of the bow of the SS Bluefields. The collapsed forward deck crane hangs off the bow of the Bluefields. An anchor can be seen hanging in place in the hawse pipe.
The 88-millimetre deck gun of the U-576 was used for surface engagements and could fire a variety of shells from the watertight ready-ammunition locker which can be found forward of the gun on the port side.
The aft section of the U-576's conning tower, also known as the wintergarten, which served as a platform for the 20-millimetre anti-aircraft flak gun.
For more information on this and other expeditions, check out the NOAA explorations website.