Mid-Atlantic gap
The Mid-Atlantic Gap is a geographical term attributed to an undefended area beyond the reach of land-based Coastal Command antisubmarine (A/S) aircraft during the Battle of the Atlantic in the Second World War. It is frequently known as The Black Pit, as well as the Atlantic Gap, Air Gap, Greenland Gap, or just "the Gap". This resulted in heavy merchant shipping losses to U-boats. The gap was eventually closed in May 1943, as growing numbers of VLR Liberators (Very Long Range models) and escort carriers became available, and as basing problems were addressed.