Could Bismarck fit a third 15-inch gun in each turret if the design avoided German cartridge-case and hoist arrangements?
Short answerA triple mounting was potentially possible with a somewhat wider turret, but the fit would be extremely tight and leave poor human access even if the barbette changed little.
NotesRemoving the historical hoist and cartridge-case constraints creates enough room to consider a third gun. The arrangement would still be extremely tight and leave inadequate access for the crew. The barbette and rotating structure might remain near the historical dimensions, but the turret itself would need some extra width. The design is possible in outline without automatically being practical in service.