World War II saw the use of semi-recessed bomb bays which, being an uncommon variation of the fully recessed bomb bay, was a design compromise for aircraft that were intended to carry bombs but did not have sufficient fuselage space for a fully recessed bomb bay; such a design did not allow for the inclusion of bomb bay doors.
During World War II, semi-recessed bomb bays were employed in aircraft intended to transport bombs, despite the lack of adequate fuselage space for fully recessed bays. These bays could not include bomb bay doors due to their design compromise.