Greyhound — Atlantic Ocean
USS Keeling escorts convoy HX-25 through the mid-Atlantic air gap — five days without air cover where U-boats hunted freely.
The 'Black Pit' was the zone beyond the range of Allied land-based aircraft where convoys had no air protection. In early 1942 the U-boats sank ships here almost at will. The crisis eased only when VLR (Very Long Range) Liberators and escort carriers closed the gap in 1943. The Battle of the Atlantic was the longest continuous military campaign of WWII.