The Boeing 377 Stratocruiser - a civilian adaptation of the C-97, a military transport which would also later be developed into the KC-97 - were derived from the B-29/B-50 family by grafting a large, bulbous passenger/cargo compartment onto the B-29/50 fuselage; this created a sharp cusp in the fuselage cross-section, as can be seen in this photo of a half-built Stratocruiser:
Such a sharp discontinuity in the fuselage profile would be expected to serve as a stress concentrator in a pressurised aircraft, like the 377/C-97/KC-97 series, and cause accelerated fatigue cracking in and around the cusp, shortening the lifespan of these fuselages; did these aircraft, in fact, experience fatigue problems emanating from the fuselage cusp, and, if so, how were they dealt with?